Searching for Hidden Costs: 

A Technology-Based Approach to the 

Energy Efficiency Gap in Light-Duty 

Vehicles 

Draft
Searching for Hidden Costs:
 

A Technology-Based Approach to the 


Energy Efficiency Gap in Light-Duty 


Vehicles
 

Draft
 

Assessment and Standards Division 

Office of Transportation and Air Quality 

U.S. Environmental Protection Agency 

NOTICE 

This technical report does not necessarily represent final EPA decisions or 

positions. It is intended to present technical analysis of issues using data 

that are currently available. The purpose in the release of such reports is to 

facilitate the exchange of technical information and to inform the public of 

technical developments. 

EPA-420-D-15-010 

November 2015 
 

 

 

 

 

 

 

 

 

 

 

Draft – Subject to Revision 

Searching for Hidden Costs: A Technology-Based Approach to the Energy Efficiency Gap in 

Light-Duty Vehicles
 

Gloria Helfand,* Jean-Marie Revelt,* Lawrence Reichle,** Kevin Bolon,* Michael
 

McWilliams,** Mandy Sha,*** Amanda Smith,*** and Robert Beach***
 

October 26, 2015
 

Abstract
 

The benefit-cost analysis of standards to reduce vehicle greenhouse gas emissions and 

improve fuel economy by the U.S. Environmental Protection Agency (EPA) and the Department 

of Transportation (DOT) displayed large net benefits from fuel savings for new vehicle buyers. 

This finding pointed to an energy efficiency gap: the amount of energy-saving technology 

provided in private markets appeared not to include all the technologies that produce net private 

benefits. The finding of a gap involves three pathways. First, the energy-saving technologies 

must be effective in achieving fuel reductions. Second, the cost estimates for those technologies 

must be lower than the present value of fuel reductions. Third, possible “hidden costs” --

undesirable aspects of the new technologies – must not exceed the net financial benefits. This 

study examines the existence of hidden costs in energy-saving technologies through a content 

analysis of auto reviews of model-year 2014 vehicles. 

Content analysis involves systematic identification in texts or other media of key 

concepts and coding of those concepts; qualitative assessments can be quantified for statistical 

analysis. Auto reviewers, as professional evaluators, are likely to be sensitive to the existence of 

positive and negative characteristics of vehicles. Although they may identify hidden costs that 

some vehicle owners may not notice, it is relatively unlikely that they would miss important 

problems. 

Results suggest that it is possible to use fuel-saving technologies on vehicles without 

imposing hidden costs. For each of the technologies examined, the number of reviews that 

evaluated them positively exceeded the number that spoke negatively. There is scant evidence in 

this analysis of a robust relationship between the technologies and vehicles’ operational 

characteristics, such as handling or acceleration. It seems possible to implement these 

technologies without adverse effects on vehicle quality; hidden costs do not appear to explain the 

efficiency gap for vehicle fuel-saving technologies. 

*Office of Transportation and Air Quality, U.S. Environmental Protection Agency 

**Oak Ridge Institute for Science and Education (ORISE) Research Participant 

***RTI International 

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Searching for Hidden Costs: A Technology-Based Approach to the Energy Efficiency Gap in 

Light-Duty Vehicles 

When the U.S. Environmental Protection Agency (EPA) and the Department of 

Transportation (DOT) developed standards to reduce vehicle greenhouse gas emissions and 

improve fuel economy, they estimated significant net benefits to the standards, with the largest 

benefits coming from fuel savings to new vehicle buyers; indeed, the fuel savings greatly 

exceeded the costs of technologies that would provide those savings (EPA and DOT 2010, 

2012). This finding pointed to an energy efficiency gap, also known as the energy paradox: the 

amount of energy-saving technology provided in private markets appears not to include all the 

technologies that produce net private benefits. For instance, although six-speed automatic 

transmissions have existed for a number of years, and appear to have a payback period of 

approximately one year relative to four-speed transmissions (Helfand and Dorsey-Palmateer 

2015), they were uncommon in new vehicles until very recently (Hula et al. 2014). Various 

authors are skeptical of these estimated savings, on the basis that, if they provided the benefits 

claimed, private markets should have led to their adoption (e.g., Allcott and Greenstone 2012). 

On the other hand, if the gap exists, then it is possible for energy efficiency regulations not only 

to address externalities, but to save consumers money (Fischer et al. 2007). The existence of the 

gap, then, has significant implications for the net benefits associated with energy efficiency 

requirements. 

A number of studies explore consumer or producer behavior at the point of deciding 

when to invest in energy-saving technologies (see, e.g., Helfand and Wolverton 2011; Allcott 

and Greenstone 2012; Gillingham and Palmer 2014). This study focuses instead on postdecision welfare – experienced utility, instead of decision utility (e.g., Kahneman and Sugden 

2005) – to examine the existence of the efficiency gap. With the standards in place, the 

existence of the gap is, in principle, an empirical matter. 

The finding of a gap involves three pathways. First, the technologies to improve fuel 

economy must be effective in achieving their fuel reductions. Second, the cost estimates for 

those fuel-saving technologies must be lower than the present value of the fuel reductions. These 

first two elements define the engineering analysis that is commonly the source of identified 

efficiency gaps. 

The third element of the gap is the possible existence of “hidden costs” of the 

technologies: undesirable aspects of the new technologies. For instance, if six-speed automatic 

transmissions were especially noisy, clunky, or otherwise worse to drive than four-speed 

automatic transmissions, those quality impacts would reflect losses to consumer welfare that the 

engineering analysis would not capture (Gillingham and Palmer 2014), and might potentially 

close the gap. An evaluation of the new technologies should consider these costs. 

This study examines the existence of hidden costs in fuel-saving technologies through a 

content analysis of auto reviews of model-year 2014 vehicles. Content analysis is a method to 

analyze text for patterns and meaning (Krippendorff 2013). It involves systematic identification 

of key concepts and coding of those concepts; in other words, qualitative assessments can be 

quantified for statistical analysis. 

The study findings suggest that it is possible to use fuel-saving technologies on vehicles 

without imposing hidden costs. For each of the technologies, the number of reviews that spoke 

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positively about the technology exceeded the number that spoke negatively of them. We also 

find few signs that any of the technologies contribute to negative ratings of vehicle operating 

characteristics, such as handling or acceleration. That there is variation in success suggests that 

there may be room for improvement: for example, some technologies may have been 

implemented more effectively in some vehicles than in others. Nevertheless, this analysis does 

not find evidence, beyond perhaps short-run implementation concerns, that hidden costs of these 

fuel-saving technologies explain the existence of the energy efficiency gap in vehicles. 

The next section of this paper provides the policy background for this work. Next, we 

describe content analysis, the method used for this study, and the details of the data collection. 

The results and conclusions follow. 

Policy Background 

In 2010 and 2012, EPA and DOT issued joint standards to reduce the greenhouse gas 

(GHG) emissions and increase the fuel economy (FE) from new vehicles for model-years (MY) 

2012 through 2025 (EPA and DOT 2010, 2012). By 2025, the standards are projected to achieve 

a fleetwide average emissions level of 163 grams/mile of carbon dioxide, approximately half the 

emissions of an average MY 2010 vehicle. If all the improvements in GHG emissions come 

from improvements in fuel economy, the standards are projected to lead to fleet average fuel 

economy of 54.5 miles per gallon (mpg). 

The standards themselves are not these values. Instead, each vehicle has a target value 

for GHG and FE based on its footprint, the area between its wheels. Larger vehicles have less 

stringent targets than smaller vehicles. Each automaker has its own individual fleetwide average 

standard based on the sales-weighted footprints of the vehicles that it makes in a given model 

year. If a manufacturer produces more small vehicles, for instance, it will have a more stringent 

target than a manufacturer that produces more large vehicles. This approach is intended to 

protect the range of vehicles available to the auto-buying public, to avoid the risk of unfairly 

benefiting one manufacturer over another, to allow for flexibility in sales mix in the face of shifts 

in market conditions, and to provide incentives to improve GHG emissions and FE across the 

entire fleet.1 Within an automaker’s fleet, if some vehicles outperform their targets, they 

generate credits that may be applied to vehicles that do not meet the targets in its own fleet, 

banked for use in future years, retired, or sold to another automaker whose fleet does not achieve 

its target. 

EPA’s and DOT’s assessments of the standards found enormous net benefits, most of 

which came from the projected fuel savings. For instance, in EPA and DOT (2010), EPA 

projected that the average cost increase for a MY 2016 vehicle would be about $950, compared 

to reduced fuel expenditures of about $4000 over the lifetime of that vehicle; the payback period 

on the initial $950 was estimated at under 3 years. Because these net benefits to vehicle buyers 

appear so substantial, the question arose why market forces did not bring them into place without 

regulation. This phenomenon – the finding of cost-effective technologies to save energy that are 

not in widespread use – has been observed in various settings, such as building insulation and 

household appliances. Indeed, it is common enough to have a name – the energy paradox, or 

1 A flat standard, which was in force for the first four decades of fuel economy requirements, may 

encourage compliance by producing small but fuel-efficient vehicles that cross-subsidize large, inefficient vehicles. 

The footprint-based standard reduces incentives for downsizing. Whether, as Whitefoot and Skerlos (2012) suggest, 

it provides an incentive for increasing vehicle size depends on the slope of the footprint curve. 

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energy efficiency gap (Helfand and Wolverton 2011; Allcott and Greenstone 2012; Gillingham 

and Palmer 2014). 

If the gap is real – that is, the present-value savings in energy costs outweigh all the costs 

of the energy-saving technology – then private markets appear not to be behaving in standard 

ways. A number of hypotheses have been raised to explain this behavior (Helfand and 

Wolverton 2011; Allcott and Greenstone 2012; Gillingham and Palmer 2014), such as imperfect 

information, excessive consumer discounting, or lack of salience of energy consumption as a 

product characteristic. Behavioral economists have found evidence of behavioral anomalies in 

market transactions (e.g., DellaVigna 2009). Specifically in the auto market, evidence is mixed: 

Busse et al. (2013) and Sallee, West, and Fann (2015) found that vehicle buyers’ revealed 

willingness to pay for fuel economy approximately matches their future fuel expenditures, while 

Allcott and Wozny (2014) estimated that vehicle buyers are willing to pay about 76 percent of 

the value of future fuel savings, and Greene (2010) finds a wide variation in estimates of 

consumer willingness to pay for fuel economy. 

On the other hand, it is possible that the gap does not actually exist, despite the 

engineering estimates. The engineering estimates may be wrong in three dimensions: they may 

underestimate the monetary costs; they may overstate the monetary benefits; or they may ignore 

“hidden costs,” undesirable changes in other attributes of the product. Allcott and Greenstone 

(2012) cite some examples of underestimated costs and overestimated benefits, as well as the 

difficulties in doing good studies of these effects. 

This study focuses on the question of the existence of the energy efficiency gap. In 

particular, it examines the question of hidden costs as a potential explanation of the energy 

efficiency gap in light-duty vehicles. If compliance with the standards adversely affect a 

vehicle’s power, handling, comfort, or other attributes, then potential vehicle buyers are likely to 

be less interested in purchasing them, and fuel-saving technologies will face obstacles in 

penetrating into the market. The existence and magnitude of hidden costs would, as noted, also 

contribute to skepticism about the existence of the energy efficiency gap. On the other hand, if 

fuel-saving technologies can be implemented without imposing hidden costs, then this 

explanation of the efficiency gap is not supported. 

Content Analysis 

Many vehicle attributes of great importance to vehicle buyers are qualitative. For 

instance, while it is possible to measure the turning radius of a vehicle, how it feels while going 

around a curve – the handling – is more difficult to quantify. Whether a fuel-saving technology 

makes the vehicle uncomfortable to drive in some way may thus be an unquantifiable attribute. 

For this reason, we looked to a method, content analysis, that can summarize a large quantity of 

text and contexts into meaningful analysis units, to understand the effects of fuel-saving 

technologies on vehicle quality. 

Content analysis is a method to analyze text in a systematic way. It is widely used in the 

humanities and social sciences to classify, measure, and evaluate themes and symbols in various 

communications media (Krippendorff 2013). At the simplest level, content analysis can involve 

counting mentions of words (as in word clouds), to highlight major topics or phrasings. In more 

complex situations, content analysis can involve coding to identify subtle messages; for instance, 

Ganahl et al. (2003) analyzed prime time television commercials in 1998 to examine the 

prevalence of genders and ages, and found women (especially older women) underrepresented 

relative to men. 

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Most of the studies of content analyses involving automobiles focus on the issue of safety 

in vehicle advertisements. Burns and Lynch (2003) found, in response to new safety 

requirements in 1979, that vehicle advertisements increased their mentions of safety features, but 

not safety itself. Ferguson et al. (2003) found that performance was the dominant advertising 

theme in U.S. television commercials for cars and passenger vans; safety was mentioned 

infrequently. Sheehan et al. (2006) examined television advertisements in Australia to examine 

the effect of new requirements on auto advertising on the ads themselves; they found a reduction 

in the occurrence of themes (Performance, Exciting/Fun to Drive) which could be considered to 

promote unsafe driving, though safety themes were in a very small proportion of ads. 

A few content analyses have considered the environmental effects of vehicles. Pollack 

and Zint (2006) found that newspaper coverage of hybrid electric vehicles focused on the 

vehicles’ environmental attributes, rather than other attributes that consumers might consider 

important when buying new vehicles. Wilson et al. (2008) analyze the content of New Zealand 

vehicle advertisements for greenhouse gas (GHG) and air pollution-related information. In their 

study, very few ads mentioned the vehicle’s fuel efficiency or reduced emissions. Nygren et al. 

consider the Finnish reform of the tax on purchase of new vehicles that increased the charge for 

higher-GHG-emitting vehicles and reduced the charge for lower-emissions vehicles. They found 

that newspaper coverage was generally positive and “treated [the reform] as an apolitical, 

technocratic issue,” though the authors express concern that the low level of coverage may have 

led to an over-optimistic assessment of its impacts. These studies do not, however, look 

specifically at the relationship between the environmental characteristics of vehicles and 

consumer response to them, as this study does. 

We chose content analysis as a tool to look for the adverse consequences of fuel-saving 

technologies, because these adverse effects are likely to show up in qualitative descriptions. A 

high-speed automatic transmission may shift roughly, for instance, or low rolling resistance tires 

may not grip the road well. Professional auto reviews are expected to be a fairly sensitive and 

relatively objective source of these qualitative descriptions. Auto reviewers are professional 

evaluators, trained to identify positive and negative characteristics of vehicles. Although they 

may identify hidden costs that some vehicle owners may not notice, it is relatively unlikely that 

they would miss important problems. 

Methods 

The first part of the study involved selection of auto reviews to be analyzed. We followed 

a conceptual hierarchy to choose relevant websites in multiple stages, consistent with the practice 

of relevance sampling described in Krippendorff (2013). We sought websites on the first page of 

search returns for keywords “new cars,” “buying a new car” and “auto reviews,” and excluded 

websites that did not have national and professional auto reviews. We then used monthly unique 

views from Quantcast.com and Compete.com to gauge Website popularity, excluded websites 

that had less than one million unique views, and added a few websites that Compete.com 

considered similar (to reduce any bias from using websites on the first page of search results). 

Finally, we screened websites to ensure that reviews had an independent assessment of vehicle 

quality (rather than a list of specification), and evidence of test driving of the reviewed vehicles.2 

This process resulted in our using the six websites in Table 1. Though these reviews are not 

2 Test driving was considered important so that reviewers would be able to evaluate operational 

characteristics, such as performance, handling, and noise. 

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necessarily representative of all auto reviews, they represent the reviews that vehicle buyers may 

be most likely to see, and may therefore influence more buyers than other sites. 

Table 1. Auto Reviews by Website* 

Website Initial Review 

Counts 

Final Review 

Counts 

Matched with 

Tech Data** 

automobilemag.com 145 144 98 

autotrader.com 233 225 163 

caranddriver.com 221 218 153 

consumerreports.org 88 88 39 

edmunds.com 113 112 109 

motortrend.com 223 221 157 

Total 1,023 1,008 719 

*After the coding was completed, we identified 15 reviews of medium-duty 

trucks that we considered out-of-sample. 

**Vehicles with enough trim-specific information to link to a database that 

identifies which technologies are on which vehicles 

The study examined all reviews of new model-year 2014 vehicles available for sale in the 

U.S. and subject to the light-duty GHG and FE standards that included evaluation after a test 

drive. After dropping reviews that did not meet these criteria, and splitting reviews that included 

discussion of more than one vehicle trim, the study coded 1,023 reviews. During the data 

cleaning process, we identified 15 reviews of medium-duty vehicles that are not subject to the 

light-duty GHG or FE standards; these were removed from the database. In addition, due to 

notice of violations from EPA regarding certain Volkswagen and Audi diesel engines and their 

emissions, we dropped 5 reviews of vehicles with those engines from our analysis (EPA 2015). 

Analyzing the relationship between operational characteristics and efficiency 

technologies might lead to biased results if reviewers do not discuss all the fuel-saving 

technologies on the list when the vehicles have them. To address this concern, we linked the 

vehicles in the content analysis with technology characteristics from publicly available EPA 

data, which is used by EPA and the Department of Energy to generate the annual Fuel Economy 

Guides. This information was supplemented with data from other publicly available sources, 

such as Edmunds and Wards, for several technology characteristics that were not available in the 

EPA data. These data are not available for all of the coded efficiency technologies in our review 

database. In particular, excluded technologies are active air dam, active grille shutters, active ride 

height, lighting-LED, mass reduction, and passive aerodynamics in addition to the general 

categories: general engine, general transmission, and general powertrain. Linking the technology 

data with the review data requires knowing the specific trim of each vehicle. In the review 

database, we did not have detailed enough information on 289 vehicles (29%) to match them 

with the technology database. After data cleaning, analyses involving the technology data (Tech 

Data in the tables that follow) use 718 reviews. 

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Reviews are themselves not conducted randomly or to reflect sales. For instance, as seen 

in Table 2, the dataset contains more reviews of Mercedes (74) than Toyota (63) vehicles. The 

review sites also sample differently: Consumer Reports reviewed 3 Mercedes (3.4 percent out of 

88 reviews), while Car and Driver reviewed 26 Mercedes, 11.9 percent out of 218 reviews. It is 

possible that auto reviewers focus on models with significant redesign; if so, the population of 

reviews is likely to have a higher proportion of new technologies than the auto population as a 

whole. The effect of this bias on the results of the analysis are unclear. To the extent that the 

new technologies are actually new to the vehicle fleet, rather than new to a particular model, this 

study may include more technologies where any kinks are not yet fully resolved, and thus may 

overstate negative impacts experienced over time. 

Table 2 also compares the total reviews to the number of distinct vehicles on the market 

for each make using data available from fueleconomy.gov. That is, it compares the proportion of 

models offered by each make to the proportion of reviews. The percentages differ by 1% or less 

for most manufacturers, suggesting that sampling bias across makes is small relative to the fleet 

of available vehicles. It is important to note that a particular make-model-trim combination may 

be reviewed several times across websites and therefore counted more than once in the “Total 

Reviews” column, while it will only be listed once in the fueleconomy.gov column; and some 

make-model-trim combinations may not be represented in the reviews. Still, this suggests that 

reviews may be roughly representative of vehicles offered, even if they are not representative of 

vehicles sold. 

Similar evidence is presented in Table 3, which lists counts by vehicle class and again 

compares with the vehicle listing from fueleconomy.gov. The most reviewed class is midsize 

cars with 23%, followed by compact cars (17%), and small SUVs (14%). Again, the majority of 

classes are within 1% of the national fleet-wide percentages. The most notable exception is 

midsize cars, which represents 17% of the fleet of available vehicles. There is no reason to 

expect the distribution of reviews to exactly match the distribution of available cars, since 

reviews will be determined by other factors, such as the redesign cycles of vehicles. However, 

we are encouraged by the similarity in our sample as it suggests we have a reasonable view of 

available vehicles and the corresponding technology. 

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Table 2. Auto reviews by website and make; compared with fueleconomy.gov counts* 

Make 

AutomobileMagazineAutoTraderCar and DriverConsumerReportsEdmundsMotorTrendTotal ReviewsMatched withTech Datafueleconomy.gov Counts 

Acura 4 4 5 2 4 5 24 (2%) 22 (3%) 16 (1%) 

Audi 3 11 9 1 7 6 37 (4%) 32 (4%) 48 (4%) 

Bentley 2 5 4 11 (1%) 11 (2%) 7 (1%) 

BMW 13 11 19 3 7 16 69 (7%) 51 (7%) 98 (8%) 

Buick 7 3 6 1 2 8 27 (3%) 13 (2%) 16 (1%) 

Cadillac 8 8 6 1 3 10 36 (4%) 17 (2%) 35 (3%) 

Chevrolet 15 16 20 10 8 16 85 (8%) 62 (9%) 77 (6%) 

Chrysler 1 2 1 4 (0.4%) 4 (1%) 14 (1%) 

Dodge 2 7 3 3 5 4 24 (2%) 16 (2%) 35 (3%) 

Ferrari 3 1 3 7 (1%) 4 (1%) 13 (1%) 

Fiat 1 3 2 1 1 8 (1%) 4 (1%) 7 (1%) 

Ford 5 14 7 5 5 11 47 (5%) 34 (5%) 88 (7%) 

GMC 1 7 4 1 4 17 (2%) 2 (0.3%) 36 (3%) 

Honda 5 8 4 5 4 8 34 (3%) 29 (4%) 30 (2%) 

Hyundai 9 2 4 4 19 (2%) 16 (2%) 38 (3%) 

Infiniti 3 9 4 1 3 5 25 (2%) 22 (3%) 29 (2%) 

Jaguar 4 6 8 2 8 28 (3%) 18 (3%) 20 (2%) 

Jeep 6 8 10 10 4 4 42 (4%) 27 (4%) 35 (3%) 

Kia 7 10 10 5 5 7 44 (4%) 38 (5%) 35 (3%) 

Land Rover 3 3 3 2 1 3 15 (1%) 9 (1%) 13 (1%) 

Lexus 2 3 4 3 5 6 23 (2%) 14 (2%) 25 (2%) 

Lincoln 3 1 2 6 (1%) 6 (1%) 16 (1%) 

Mazda 8 9 9 4 6 13 49 (5%) 33 (5%) 25 (2%) 

Mercedes 6 14 26 3 6 19 74 (7%) 56 (8%) 85 (7%) 

Mini Cooper 5 1 1 4 11 (1%) 9 (1%) 46 (4%) 

Mitsubishi 3 4 2 3 2 3 17 (2%) 12 (2%) 19 (2%) 

Nissan 4 19 6 2 5 4 40 (4%) 38 (5%) 51 (4%) 

Porsche 6 3 13 1 2 9 34 (3%) 25 (3%) 52 (4%) 

Ram 2 1 1 1 2 7 (1%) 1 (0.1%) 13 (1%) 

Rolls Royce 3 1 2 3 9 (1%) 9 (1%) 7 (1%) 

Scion 1 1 1 1 4 (0.4%) 3 (0.4%) 9 (1%) 

Smart 1 1 (0.1%) 1 (0.1%) 4 (0.3%) 

Subaru 4 5 2 3 3 8 25 (2%) 17 (2%) 23 (2%) 

Toyota 6 17 14 5 7 14 63 (6%) 40 (6%) 58 (5%) 

Volkswagen** 1 6 9 11 6 4 37 (4%) 21 (3%) 50 (4%) 

Volvo 2 3 5 (0.5%) 3 (0.4%) 13 (1%) 

Other*** 43 (3%) 

Total 144 225 218 88 112 221 1,008 719 1,229 

*Percentages in parentheses represent percentage of column total. 

**In the analysis that follows, we exclude reviews of 5 Volkswagen/Audi diesels alleged to be in 

violation of emissions standards. 

***Other category for fueleconomy.gov includes Aston Martin (7), Bugatti (1), BYD (1), Lamborghini (7), 

Lotus (4), Maserati (6), McLaren (3), Mobility Ventures LLC (2), Pagani (1), Roush (7), SRT (1), and Tesla Motors 

(3). 

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Table 3. Reviews by Vehicle Class; compared with fueleconomy.gov counts* 

Final 

Review Matched with fueleconomy.gov 

Vehicle Class Count Tech Data** Count 

Subcompact Cars 79 (8%) 68 (9%) 101 (8%) 

Minicompact Cars 13 (1%) 12 (2%) 52 (4%) 

Compact Cars 173 (17%) 126 (18%) 201 (16%) 

Two Seaters 81 (8%) 52 (7%) 93 (8%) 

Midsize Cars 229 (23%) 147 (20%) 215 (17%) 

Large Cars 87 (9%) 71 (10%) 104 (8%) 

Small Station Wagons 26 (3%) 22 (3%) 36 (3%) 

Midsize Station Wagons 8 (1%) 8 (1%) 4 (0.3%) 

Passenger Vans 1 (0.1%) 16 (1%) 

Minivans 15 (1%) 15 (2%) 14 (1%) 

Small SUVs 143 (14%) 104 (14%) 179 (15%) 

Standard SUVs 89 (9%) 69 (10%) 116 (9%) 

Small Pickup Trucks 1 (0.1%) 14 (1%) 

Standard Pickup Trucks 41 (4%) 7 (1%) 54 (4%) 

Not Recorded 22 (2%) 18 (3%) 

Other*** 30 (2%) 

Total 1,008 719 1,229 

*Percentages in parentheses represent percentage of column total. 

** Vehicles with enough trim-specific information to link to a database that identifies which 

technologies are on which vehicles 

***Other category for fueleconomy.gov contains "Special Purpose Vehicle 2WD", "Special Purpose 

Vehicle 4WD", and Cargo Vans. 

When analyzing each review, we coded for technologies (e.g., high-speed automatic 

transmissions) most likely to affect the requirements for reduced GHG emissions. The list of 

technologies came from reviewing the technologies proposed for compliance purposes in EPA 

and DOT (2010 and 2012), as well as professional engineering judgment. In addition, we coded 

for reviews of operational characteristics such as acceleration, handling, drivability, noise, and 

comfort. This allows us to search for patterns in negative (or positive) operational reviews 

conditional on mentions of a specific technology, which could suggest the presence of hidden 

costs. Table 4 lists the coded efficiency technologies and operational characteristics considered 

in this study. 

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Table 4. Efficiency Technology and Operational Characteristics Coded 

Parent Hierarchy Coding Level 

Efficiency Technology 

Active Air Dam Active Air Dam 

Active Grille Shutters Active Grille Shutters 

Active Ride Height Active Ride Height 

Electric Assist or Low Drag Brakes Electric Assist or Low Drag Brakes 

Electronic Power Steering Electronic Power Steering 

Lighting – LED Lighting-LED 

Low Rolling Resistance Tires Low Rolling Resistance Tires 

Mass Reduction Mass Reduction 

Passive Aerodynamics Passive Aerodynamics 

Powertrain 

Engine 

Cylinder Deactivation 

Diesel 

Full Electric 

Gasoline Direct Injection (GDI) 

General Engine 

Hybrid 

Plug-in Hybrid Electric 

Stop-start 

Turbocharged 

General Powertrain General Powertrain 

Transmission 

Continuously Variable Transmission (CVT) 

Dual-clutch Transmission (DCT) 

General Transmission 

High Speed Automatic 

Operational Characteristics 

Charging Charging 

Drivability 

Acceleration 

Acceleration Capability-power-torque 

Acceleration feel-smoothness-responsiveness 

General Acceleration 

Braking 

Brake Feel-responsiveness 

General Braking 

Stopping Ability 

Handling 

Cornering Ability-grip-balance-body control 

General Handling 

Steering Feel-controllability-responsiveness 

General Drivability General Drivability 

Fuel Economy Fuel Economy 

Noise 

General Noise 

Interior Noise 

Powertrain Noise 

Tire-road Noise 

Wind Noise 

Range Range 

Ride Comfort Ride Comfort 

Vibration 

Chassis Vibration 

General Vibration 

Powertrain Vibration 

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Each review was coded for all mentions of these technologies and operational 

characteristics. For instance, consider the following quote from a review: “We like the effortless 

power and the smooth transmission, but the auto start/stop system has more delay than some, the 

throttle can be a bit on the jumpy side and the light steering is disconcerting.” (Edmunds 2014). 

The “smooth transmission,” elsewhere identified as a 7-speed automatic, was coded as positive 

for high-speed automatic transmission; the stop/start system, having “more delay than some,” 

was coded as negative. In addition, “effortless power” was coded as positive for acceleration 

capability, while the “disconcerting” steering was coded as negative for steering feel. 

To conduct the coding, an adjudicator trained two coders to recognize the technologies 

and characteristics and their synonyms. As part of the training, the coders were given the same 

reviews to code, to check for inter-coder reliability (to ensure replicability of the results). At the 

end of the training, the coders reached above 90% agreement and a Cohen’s Kappa coefficient of 

0.6 (fair agreement), again followed by code by code review and debriefing. After the training, 

we continued with independent learning and assessment until the coders reached above 90% 

agreement and a Cohen’s Kappa coefficient of 0.8 (where 0.75 is considered “excellent 

agreement”). The coding operation officially started after that. The coders examined reviews for 

mentions of the technologies and operational characteristics, and then, in context, evaluated 

whether the reviewers spoke positively, negatively, or neutrally about them. Checks on intercoder reliability were conducted regularly to ensure quality. 

We coded a total of 1,023 auto reviews (1,008 after data cleaning) from the six websites 

for model year 2014 vehicles, representing 36 manufacturers and 14 official vehicle class 

categories (using the classification system of the website fueleconomy.gov). Because each 

review had multiple individual codes (e.g., for engine and transmission), the total number of 

individual efficiency technology codes is 3,535, or about 3.5 codes per review. The total number 

of operational characteristics coded was 12,623, or 12.6 codes per review. In terms of publication 

dates, 43% of the auto reviews were published in 2013, while the rest were published in 2014 

(26%) or no dates were recorded (31%).3 

Results 

Table 5 presents counts of individual codes for vehicle technologies, where any one 

review may have multiple codes covering the same or different technologies represented in the 

vehicle. For every technology, the number of positive codes exceeds the number of negative 

codes. In the aggregate, 71 percent of the codes for technologies are positive, compared to 13 

percent neutral and 16 percent negative. At face value, this result suggests that the new 

technologies are generally being received positively. However, this representation of the results 

could possibly be due to positive reviews having multiple references, while negative reviews get 

fewer mentions. 

Table 6 addresses this concern by summarizing the results when the results are 

aggregated to individual reviews. If an item to be coded was mentioned multiple times in a 

review, then its treatment depends on whether it always was coded the same way. If, for 

example, all the codes are positive, then, at the review level, it is listed once in the positive 

column. If, on the other hand, it is mentioned in both a positive and a negative way, then it gets 

listed twice – once for positive, and once for negative. This approach gives slightly more weight 

3 Many MY2014 vehicles were available to professional auto reviewers, and even to the general public, in 

2013. 

11
 
 

 

Draft – Subject to Revision 

to mixed reviews, perhaps the opposite bias from the code-level analysis. It, nevertheless, shows 

the same pattern: the positive reviews outweigh the negative reviews for all fuel-saving 

technologies. In the aggregate, reviews with mentions of the technologies have positive 

evaluations 68 percent of the time; neutral evaluations 16 percent; and negative evaluations 16 

percent of the time. This result also suggests that it is possible, for any of these technologies, to 

implement them in ways that auto reviewers find favorable. 

Table 5: Total number of positive, negative, and neutral codes by efficiency technology 

Parent Hierarchy Coding Level Negative Neutral Positive Total 

Active Air Dam Active Air Dam - - - - 6 100% 6 

Active Grille Shutters Active Grille Shutters - - - - 1 100% 1 

Active Ride Height Active Ride Height - - 1 33% 2 67% 3 

Electric Assist/Low Drag Brakes Electric Assist/Low Drag 

Brakes 1 13% 3 38% 4 50% 8 

Electronic power steering Electronic Power Steering 51 23% 43 19% 129 58% 223 

Lighting - LED Lighting-LED 1 4% 2 9% 20 87% 23 

Low Rolling Resistance Tires Low Rolling Resistance Tires 4 24% 5 29% 8 47% 17 

Mass Reduction Mass Reduction - - 12 13% 80 87% 92 

Passive Aerodynamics Passive Aerodynamics 4 10% 7 17% 30 73% 41 

Powertrain 

Engine 

Cylinder Deactivation 1 3% 4 10% 35 88% 40 

Diesel 13 9% 11 8% 122 84% 146 

Full Electric 4 11% 7 20% 24 69% 35 

GDI 7 9% 7 9% 63 82% 77 

General Engine 154 15% 112 11% 740 74% 1,006 

Hybrid 28 19% 13 9% 104 72% 145 

Plug-In Hybrid Electric 7 13% 6 11% 42 76% 55 

Stop-Start 15 27% 8 14% 33 59% 56 

Turbocharged 23 7% 25 8% 285 86% 333 

General Powertrain General Powertrain 13 11% 19 16% 90 74% 122 

Transmission 

CVT 57 31% 31 17% 97 52% 185 

DCT 27 25% 12 11% 67 63% 106 

General Transmission 47 22% 28 13% 134 64% 209 

High Speed Automatic 117 19% 101 17% 388 64% 606 

Total 574 16% 457 13% 2,504 71% 3,535 

*These counts exclude reviews of 5 Volkswagen/Audi diesels alleged to be in violation of emissions standards. 

12
 
 

 

 

 

 

 

 

 

 

Draft – Subject to Revision 

Table 6: Number of positive, negative, and neutral evaluations by auto review 

Parent Hierarchy Coding Level Negative Neutral Positive Total 

Active Air Dam Active Air Dam - - - - 6 100% 6 

Active Grille Shutters Active Grille Shutters - - - - 1 100% 1 

Active Ride Height Active Ride Height - - 1 33% 2 67% 3 

Electric Assist or Low Drag 

Brakes 

Electric Assist Or Low Drag 

Brakes 1 14% 3 43% 3 43% 7 

Electronic power steering Electronic Power Steering 45 22% 42 20% 121 58% 208 

Lighting - LED Lighting-LED 1 5% 2 10% 17 85% 20 

Low Rolling Resistance Tires Low Rolling Resistance Tires 4 24% 5 29% 8 47% 17 

Mass Reduction Mass Reduction - - 9 12% 65 88% 74 

Passive Aerodynamics Passive Aerodynamics 4 10% 7 18% 29 73% 40 

Powertrain 

Engine 

Cylinder Deactivation 1 3% 4 11% 30 86% 35 

Diesel 7 12% 9 15% 44 73% 60 

Full Electric 2 9% 6 27% 14 64% 22 

GDI 6 9% 6 9% 54 82% 66 

General Engine 104 16% 95 15% 443 69% 642 

Hybrid 16 23% 10 14% 45 63% 71 

Plug-In Hybrid Electric 4 14% 6 21% 18 64% 28 

Stop-Start 14 27% 7 14% 30 59% 51 

Turbocharged 20 9% 23 10% 180 81% 223 

General Powertrain General Powertrain 8 8% 19 18% 78 74% 105 

Transmission 

CVT 35 31% 20 18% 57 51% 112 

DCT 16 24% 10 15% 42 62% 68 

General Transmission 30 18% 26 16% 108 66% 164 

High Speed Automatic 60 14% 81 20% 273 66% 414 

Total 378 16% 391 16% 1,668 68% 2,437 

*These counts exclude reviews of 5 Volkswagen/Audi diesels alleged to be in violation of emissions standards. 

Because the results by codes and by reviews are similar, the following discussion focuses 

on the results by review. 

The mentions of the technologies in the reviews are not very frequent. As noted above, 

there are about 3.5 codes of any of these technologies per review; excluding General Engine, 

General Powertrain, and General Transmission (which are not specific fuel-saving technologies), 

there are about 2.2 codes of fuel-saving technologies per review. The most mentioned fuelsaving technologies are high-speed automatic transmissions, turbocharging, electronic power 

steering (EPS), and continuously variable transmissions (CVTs); other technologies are 

mentioned in fewer than 10 percent of the reviews. It is important to note that absence of 

mention of a technology in a review does not mean that the technology is absent; it means that 

the reviewer did not comment on it. It seems plausible that reviewers would notice and comment 

on undesirable features; a lack of mention when a technology is present may then be interpreted 

as an absence of a hidden cost. If so, the positive and neutral codings may under-represent the 

true effect of the technology. To examine this question, as discussed above, we were able to 

match 71% of the vehicles reviewed with technology data. 

The technologies mentioned most positively in percentage terms include active air dams 

(100 percent of 6 reviews), active grille shutters (100 percent of 1 review), mass reduction (88 

percent of 74 reviews), cylinder deactivation (86 percent of 35 reviews), LED lights (85 percent 

13
 
 

 

 

 

 

 

 

 

 

 

Draft – Subject to Revision 

of 20 reviews), gasoline direct injection (GDI, 82 percent of 66 reviews), and turbocharging (81 

percent of 223 reviews). With the exception of turbocharging, these technologies are mentioned 

in less than 10 percent of reviews. The proportion of the reviews that mention one of these 

technologies is higher for luxury brands than for standard brands:4 172 out of 403 reviews 

(43%) for a luxury brand mention one or more of these technologies, while 162 out of 600 

reviews (27%) for a standard brand mention one or more. It is not possible to say whether these 

technologies are considered high-end, and thus more suitable for luxury vehicles, or whether 

they are being implemented with high quality for these uses. 

The technologies with at least 20 percent of negative reviews include continuously 

variable transmissions (CVTs, 31 percent of 112 reviews), stop-start (27 percent of 51 reviews), 

low rolling resistance tires (24 percent of 17 reviews), dual-clutch transmissions (DCTs) (24 

percent of 68 reviews), hybrids (23 percent of 71 reviews), and electronic power steering (EPS, 

22 percent of 208 reviews). With the exceptions of CVTs and EPS, these technologies were also 

mentioned in less than 10 percent of reviews. These technologies were mentioned in reviews for 

luxury brands at close to the same rate as for standard brands: 37% (151 out of 403) of reviews 

for luxury brands, and 34% (204 out of 600) reviews for standard brands mentioned one or more 

of these technologies. As a group, the proportion of negative reviews is very similar for luxury 

(27%) and standard (23%) brands. Unlike the better-reviewed technologies, these technologies 

appear not to be over-represented in the luxury segment. Even the worst reviewed of these 

technologies (CVTs), though, still had 51 percent positive mentions and 18 percent neutral 

mentions. 

Table 7 shows the percent of negative reviews for both technologies and operational 

characteristics by manufacturer. As it shows, there is a great deal of variation, for both 

categories, in the proportion of negative reviews. Bentley, Chrysler, and Rolls Royce have no 

negative evaluations of efficiency technologies (out of a total of 39 coded technologies), while 

Fiat had 53 percent of 15 coded technologies evaluated as negative. For operational 

characteristics, Acura, Audi, Bentley, Ram, Rolls Royce, and Smart had less than 10 percent of 

the characteristics evaluated negatively (Smart had only 1, positive, code); Mitsubishi had 

negative evaluations of 56 percent of its codes for operational characteristics. The correlation 

between these percentages is 0.80: companies that are well rated on operational characteristics 

also appear to implement efficiency technologies positively. 

4 Luxury brands are here defined as Acura, Audi, Bentley, BMW, Cadillac, Ferrari, Infiniti, Jaguar, Land 

Rover, Lexus, Lincoln, Mercedes, Porsche, Rolls Royce, and Volvo. These covered 403 of the 1003 reviews. 

14
 
 

 

 

Draft – Subject to Revision 

Table 7: Percent Negative Reviews of Efficiency Technologies and Operational Characteristics, 

by Manufacturer 

Make % Negative 

Tech Reviews 

% Negative 

Operational 

Characteristics 

Reviews 

Make % Negative 

Tech Reviews 

% Negative 

Operational 

Characteristics 

Reviews 

Acura 6.9% 8.5% Kia 13.3% 15.0% 

Audi 5.9% 9.3% Land Rover 4.5% 13.4% 

Bentley 0.0% 6.1% Lexus 26.4% 21.6% 

BMW 9.8% 11.0% Lincoln 38.5% 24.4% 

Buick 27.3% 22.3% Mazda 8.9% 13.6% 

Cadillac 9.2% 12.2% Mercedes 14.1% 13.9% 

Chevrolet 14.0% 14.8% Mini Cooper 22.7% 20.0% 

Chrysler 0.0% 10.0% Mitsubishi 39.1% 56.3% 

Dodge 12.5% 20.6% Nissan 34.1% 25.8% 

Ferrari 9.5% 10.4% Porsche 10.9% 12.5% 

Fiat 53.3% 39.1% Ram 11.1% 6.5% 

Ford 16.4% 15.6% Rolls Royce 0.0% 4.6% 

GMC 14.3% 18.2% Scion 16.7% 36.4% 

Honda 7.7% 13.7% Smart -- 0.0% 

Hyundai 25.5% 22.1% Subaru 32.8% 21.8% 

Infiniti 28.1% 19.7% Toyota 14.0% 22.5% 

Jaguar 3.8% 11.2% Volkswagen 13.2% 15.4% 

Jeep 26.9% 25.1% Volvo 40.0% 30.0% 

For further assessment of the relationship between vehicle technologies and hidden costs, 

we examined the relationship between evaluations of operational characteristics – specifically, 

the negative evaluations -- and the technologies. 

Table 8 and Table 9 provide the fraction of reviews where an efficiency technology is 

mentioned (Table 8) or appears in the technology data (Table 9) with negative operational 

characteristics. For comparison, these tables include the fraction of reviews where the efficiency 

technology is not mentioned (Table 8) or not included (Table 9) with negative evaluations of that 

characteristic, and whether those proportions are statistically different based on simple t-tests of 

differences in means. For instance, in Table 8, for the subset of reviews that mention CVT (83 

reviews), 40% of those reviews also negatively review the acceleration capability. This differs by 

+26 percentage points from the subset of reviews that do not mention CVT, i.e. 14% of reviews 

that do not mention CVT also give a negative review of acceleration capability. This difference 

is statistically significant at the 1% level base on the simple t-test. This result is nearly identical 

to the analogous result in Table 9 using the tech data for presence of CVT. In that case, 41% of 

vehicles with CVT get a negative review on acceleration capability compared to 14% of vehicles 

without CVT, a difference which is again significant at the 1% level. 

15
 
 

 

 

 

Draft – Subject to Revision 

For many other technologies the differences are negative, i.e., vehicles with the 

technologies have fewer negative reviews. In Table 8, for example, vehicles with mentions of 

stop-start technology have a negative rating on acceleration capability 6% of the time, compared 

to 17% of cars without stop-start technology, for a difference of -11%. This difference is also 

significant at the 1% level based on the simple t-test. Once again, this result is very close to the 

result using the tech data from Table 9 where 8% of vehicles with stop-start receive a negative 

rating on acceleration capability, compared to 18% of vehicles without stop-start. 

As noted above, we do not have tech data for all of the coded efficiency technologies in 

our review database. Nonetheless, the results are generally similar for technologies that are 

represented in both Table 8 and Table 9. 

16
 
 

 

 

 

Draft – Subject to Revision 

Table 8: Share of reviews with negative operational reviews conditional on efficiency technology Steering Feel Cornering Ability General Drivability General Handling Acceleration Feel Acceleration Capability General Acceleration Brake Feel Stopping Ability General Braking Tire-Road Noise 

Active Air Dam (N=6) 0.00 

-.15*** 

0.00 

-.09*** 

0.00 

-.12*** 

0.17 

0.09 

0.00 

-.08*** 

0.00 

-.16*** 

0.00 

-.02*** 

0.00 

-.05*** 

0.00 

-.03*** 

0.00 

-.02*** 

0.00 

-.07*** 

Active Grille Shutters 

(N=1) 

0.00 

-0.15 

0.00 

-0.09 

0.00 

-0.12 

0.00 

-0.08 

0.00 

-0.08 

0.00 

-0.16 

0.00 

-0.02 

0.00 

-0.05 

0.00 

-0.03 

0.00 

-0.02 

0.00 

-0.07 

Active Ride Height 

(N=3) 

0.00 

-.15*** 

0.00 

-.09*** 

0.00 

-.12*** 

0.00 

-.08*** 

0.00 

-.08*** 

0.33 

0.17 

0.00 

-.02*** 

0.00 

-.05*** 

0.00 

-.03*** 

0.00 

-.02*** 

0.00 

-.07*** 

Low Resistance Tires 

(N=14) 

0.21 

0.07 

0.29 

0.2 

0.21 

0.1 

0.07 

-0.01 

0.21 

0.14 

0.21 

0.05 

0.07 

0.05 

0.07 

0.03 

0.07 

0.04 

0.00 

-.02*** 

0.07 

0 

Electronic Power 

Steering (N=193) 

0.28 

.17*** 

0.10 

0.01 

0.08 

-.05** 

0.05 

-.04* 

0.08 

0 

0.13 

-0.04 

0.01 

-.02* 

0.06 

0.02 

0.06 

.03* 

0.02 

-0.01 

0.09 

0.03 

Turbocharged 

(N=195) 

0.14 

-0.01 

0.10 

0.01 

0.09 

-0.03 

0.04 

-.05*** 

0.08 

0.01 

0.13 

-0.04 

0.01 

-.02*** 

0.03 

-0.02 

0.02 

-0.01 

0.02 

0 

0.07 

0 

GDI (N=62) 0.13 

-0.02 

0.02 

-.08*** 

0.08 

-0.04 

0.03 

-.05** 

0.08 

0.01 

0.21 

0.05 

0.00 

-.03*** 

0.02 

-.03* 

0.05 

0.02 

0.00 

-.02*** 

0.05 

-0.02 

Cylinder Deactivation 

(N=35) 

0.17 

0.03 

0.00 

-.1*** 

0.06 

-0.06 

0.03 

-.06* 

0.06 

-0.02 

0.20 

0.04 

0.00 

-.02*** 

0.03 

-0.02 

0.11 

0.09 

0.00 

-.02*** 

0.03 

-0.04 

Diesel (N=47) 0.09 

-0.06 

0.04 

-0.05 

0.04 

-.08** 

0.00 

-.09*** 

0.02 

-.06** 

0.17 

0.01 

0.02 

0 

0.02 

-0.03 

0.02 

-0.01 

0.00 

-.02*** 

0.02 

-.05** 

Hybrid (N=54) 0.15 

0 

0.09 

0 

0.22 

.11* 

0.07 

-0.01 

0.13 

0.06 

0.17 

0 

0.02 

-0.01 

0.15 

.11** 

0.06 

0.03 

0.06 

0.04 

0.00 

-.08*** 

Plug-In Hybrid 

Electric (N=18) 

0.06 

-0.09 

0.11 

0.02 

0.11 

0 

0.11 

0.03 

0.00 

-.08*** 

0.17 

0 

0.06 

0.03 

0.11 

0.07 

0.06 

0.03 

0.06 

0.04 

0.06 

-0.02 

Full Electric (N=18) 0.11 

-0.04 

0.06 

-0.04 

0.17 

0.05 

0.06 

-0.03 

0.22 

0.15 

0.22 

0.06 

0.06 

0.03 

0.06 

0.01 

0.06 

0.03 

0.00 

-.02*** 

0.00 

-.07*** 

Stop-Start (N=49) 0.18 

0.04 

0.06 

-0.03 

0.10 

-0.01 

0.06 

-0.02 

0.08 

0.01 

0.06 

-.11*** 

0.02 

0 

0.04 

-0.01 

0.02 

-0.01 

0.02 

0 

0.10 

0.03 

General Engine 

(N=547) 

0.14 

0 

0.11 

.04** 

0.14 

.05** 

0.09 

0.01 

0.07 

-0.01 

0.19 

.06*** 

0.03 

0.01 

0.04 

-0.01 

0.03 

0 

0.01 

-.02** 

0.09 

.04** 

High Speed 

Automatic (N=351) 

0.15 

0 

0.10 

0.01 

0.10 

-0.02 

0.09 

0.01 

0.07 

-0.02 

0.15 

-0.03 

0.01 

-.02*** 

0.05 

0 

0.03 

0 

0.01 

-.02** 

0.09 

0.03 

CVT (N=83) 0.24 

.1** 

0.14 

0.06 

0.31 

.22*** 

0.18 

.11** 

0.17 

.1** 

0.40 

.26*** 

0.02 

0 

0.13 

.09** 

0.08 

.06* 

0.02 

0 

0.11 

0.04 

DCT (N=54) 0.15 

0 

0.13 

0.04 

0.07 

-0.04 

0.11 

0.03 

0.07 

0 

0.17 

0 

0.02 

-0.01 

0.06 

0.01 

0.04 

0.01 

0.02 

0 

0.15 

0.08 

General Transmission 

(N=138) 

0.17 

0.02 

0.06 

-.04* 

0.11 

-0.01 

0.06 

-0.03 

0.09 

0.01 

0.17 

0.01 

0.04 

0.01 

0.06 

0.01 

0.03 

0 

0.07 

.05** 

0.12 

.05* 

General Powertrain 

(N=101) 

0.15 

0 

0.06 

-0.04 

0.14 

0.03 

0.11 

0.03 

0.07 

-0.01 

0.19 

0.03 

0.05 

0.03 

0.07 

0.03 

0.05 

0.02 

0.01 

-0.01 

0.10 

0.03 

Elec Assist Or Low 

Drag Brakes (N=6) 

0.17 

0.02 

0.00 

-.09*** 

0.00 

-.12*** 

0.00 

-.08*** 

0.17 

0.09 

0.17 

0 

0.00 

-.02*** 

0.00 

-.05*** 

0.17 

0.14 

0.00 

-.02*** 

0.00 

-.07*** 

Lighting-LED (N=17) 0.24 

0.09 

0.12 

0.03 

0.24 

0.12 

0.24 

0.16 

0.00 

-.08*** 

0.18 

0.01 

0.00 

-.02*** 

0.00 

-.05*** 

0.00 

-.03*** 

0.00 

-.02*** 

0.24 

0.17 

Mass Reduction 

(N=73) 

0.10 

-0.05 

0.07 

-0.03 

0.04 

-.08*** 

0.04 

-.04* 

0.01 

-.07*** 

0.10 

-.07* 

0.01 

-0.01 

0.07 

0.02 

0.01 

-0.02 

0.01 

-0.01 

0.08 

0.01 

Passive Aerodynamics 

(N=38) 

0.11 

-0.04 

0.08 

-0.01 

0.05 

-.07* 

0.05 

-0.03 

0.03 

-.05* 

0.08 

-.09* 

0.00 

-.02*** 

0.08 

0.03 

0.03 

0 

0.08 

0.06 

0.05 

-0.02 

The top number in each cell is the fraction of reviews with a negative coded statement about the operational 

characteristic (column) conditional on also having a coded statement about the efficiency technology (row). 

The second number measures the difference with all other reviews that do not have coded statements about 

the technology. Significance with 10% (*), 5% (**), and 1% (***) is estimated using t-tests for differences 

in means. 

17
 
 

 

Draft – Subject to Revision 

Table 8 Continued 

WindNoiseInterior NoisePowertrainNoiseGeneralNoiseChassisVibrationPowertrainVibrationGeneralVibrationRideComfortFuel EconomyRangeCharging 

Active Air Dam (N=6) 0.00 

-.03*** 

0.00 

-.02*** 

0.00 

-.15*** 

0.00 

-.06*** 

0.00 

-.01*** 

0.00 

-.01*** 

0.00 

-.02*** 

0.17 

0.02 

0.00 

-.16*** 

0.00 

-.01*** 

0.00 

0* 

Active Grille Shutters 

(N=1) 

0.00 

-0.03 

0.00 

-0.02 

0.00 

-0.14 

0.00 

-0.06 

0.00 

-0.01 

0.00 

-0.01 

0.00 

-0.02 

0.00 

-0.15 

0.00 

-0.16 

0.00 

-0.01 

0.00 

0 

Active Ride Height 

(N=3) 

0.00 

-.03*** 

0.00 

-.02*** 

0.00 

-.14*** 

0.00 

-.06*** 

0.00 

-.01*** 

0.00 

-.01*** 

0.00 

-.02*** 

0.00 

-.15*** 

0.00 

-.16*** 

0.00 

-.01*** 

0.00 

0* 

Low Resistance Tires 

(N=14) 

0.00 

-.03*** 

0.00 

-.02*** 

0.21 

0.07 

0.14 

0.09 

0.00 

-.01*** 

0.00 

-.01*** 

0.07 

0.05 

0.21 

0.07 

0.00 

-.16*** 

0.07 

0.07 

0.00 

0* 

Electronic Power 

Steering (N=193) 

0.03 

0 

0.00 

-.02*** 

0.15 

0 

0.04 

-.03* 

0.02 

0.02 

0.01 

0 

0.01 

-0.01 

0.13 

-0.02 

0.12 

-.05* 

0.01 

0 

0.00 

0* 

Turbocharged 

(N=195) 

0.01 

-.02** 

0.01 

-0.01 

0.14 

-0.01 

0.03 

-.04*** 

0.01 

0 

0.02 

0.01 

0.02 

0 

0.12 

-0.03 

0.13 

-0.03 

0.00 

-.01*** 

0.00 

0* 

GDI (N=62) 0.03 

0 

0.02 

0 

0.06 

-.09** 

0.05 

-0.01 

0.00 

-.01*** 

0.00 

-.01*** 

0.03 

0.01 

0.19 

0.05 

0.03 

-.14*** 

0.00 

-.01*** 

0.00 

0* 

Cylinder Deactivation 

(N=35) 

0.00 

-.03*** 

0.00 

-.02*** 

0.09 

-0.06 

0.03 

-0.03 

0.00 

-.01*** 

0.03 

0.02 

0.03 

0.01 

0.23 

0.08 

0.06 

-.11** 

0.00 

-.01*** 

0.00 

0* 

Diesel (N=47) 0.02 

-0.01 

0.00 

-.02*** 

0.11 

-0.04 

0.04 

-0.02 

0.00 

-.01*** 

0.02 

0.01 

0.00 

-.02*** 

0.04 

-.11*** 

0.06 

-.1*** 

0.00 

-.01*** 

0.00 

0* 

Hybrid (N=54) 0.00 

-.03*** 

0.00 

-.02*** 

0.20 

0.06 

0.09 

0.04 

0.00 

-.01*** 

0.00 

-.01*** 

0.00 

-.02*** 

0.11 

-0.04 

0.17 

0.01 

0.00 

-.01*** 

0.00 

0* 

Plug-In Hybrid 

Electric (N=18) 

0.00 

-.03*** 

0.00 

-.02*** 

0.33 

0.19 

0.00 

-.06*** 

0.00 

-.01*** 

0.00 

-.01*** 

0.00 

-.02*** 

0.00 

-.15*** 

0.06 

-.11* 

0.28 

.28** 

0.11 

0.11 

Full Electric (N=18) 0.00 

-.03*** 

0.00 

-.02*** 

0.11 

-0.03 

0.06 

0 

0.00 

-.01*** 

0.00 

-.01*** 

0.00 

-.02*** 

0.17 

0.02 

0.06 

-.11* 

0.11 

0.11 

0.06 

0.05 

Stop-Start (N=49) 0.00 

-.03*** 

0.00 

-.02*** 

0.12 

-0.02 

0.10 

0.05 

0.00 

-.01*** 

0.02 

0.01 

0.04 

0.02 

0.27 

.12* 

0.16 

0 

0.02 

0.01 

0.00 

0* 

General Engine 

(N=547) 

0.03 

0.01 

0.02 

.02** 

0.14 

0 

0.06 

0.01 

0.01 

.01*** 

0.02 

.01** 

0.02 

0.01 

0.19 

.08*** 

0.20 

.08*** 

0.00 

-.01** 

0.00 

0 

High Speed 

Automatic (N=351) 

0.03 

0.01 

0.02 

0.01 

0.14 

0 

0.05 

-0.02 

0.01 

0 

0.01 

0.01 

0.02 

0.01 

0.19 

.06** 

0.16 

0 

0.00 

-0.01 

0.00 

0* 

CVT (N=83) 0.07 

0.05 

0.02 

0.01 

0.37 

.25*** 

0.18 

.13*** 

0.01 

0.01 

0.02 

0.02 

0.04 

0.02 

0.18 

0.04 

0.25 

.1** 

0.00 

-.01*** 

0.00 

0* 

DCT (N=54) 0.00 

-.03*** 

0.04 

0.02 

0.09 

-0.05 

0.06 

0 

0.02 

0.01 

0.02 

0.01 

0.06 

0.04 

0.24 

0.1 

0.04 

-.13*** 

0.00 

-.01*** 

0.00 

0* 

General Transmission 

(N=138) 

0.07 

.04* 

0.03 

0.02 

0.14 

0 

0.10 

.05* 

0.02 

0.02 

0.00 

-.01*** 

0.01 

-0.01 

0.18 

0.04 

0.17 

0.01 

0.00 

-.01*** 

0.01 

0 

General Powertrain 

(N=101) 

0.05 

0.02 

0.02 

0 

0.16 

0.02 

0.15 

.1*** 

0.01 

0 

0.00 

-.01*** 

0.02 

0 

0.15 

0 

0.20 

0.04 

0.01 

0 

0.00 

0* 

Elec Assist Or Low 

Drag Brakes (N=6) 

0.00 

-.03*** 

0.00 

-.02*** 

0.17 

0.02 

0.00 

-.06*** 

0.00 

-.01*** 

0.00 

-.01*** 

0.00 

-.02*** 

0.00 

-.15*** 

0.00 

-.16*** 

0.00 

-.01*** 

0.00 

0* 

Lighting-LED (N=17) 0.00 

-.03*** 

0.18 

0.16 

0.06 

-0.09 

0.12 

0.06 

0.00 

-.01*** 

0.00 

-.01*** 

0.00 

-.02*** 

0.24 

0.09 

0.12 

-0.04 

0.00 

-.01*** 

0.00 

0* 

Mass Reduction 

(N=73) 

0.03 

0 

0.00 

-.02*** 

0.11 

-0.04 

0.04 

-0.02 

0.00 

-.01*** 

0.01 

0 

0.03 

0.01 

0.18 

0.03 

0.03 

-.14*** 

0.00 

-.01*** 

0.01 

0.01 

Passive Aerodynamics 

(N=38) 

0.03 

0 

0.03 

0.01 

0.11 

-0.04 

0.05 

-0.01 

0.00 

-.01*** 

0.00 

-.01*** 

0.00 

-.02*** 

0.13 

-0.02 

0.13 

-0.03 

0.03 

0.02 

0.00 

0* 

The top number in each cell is the fraction of reviews with a negative coded statement about the operational 

characteristic (column) conditional on also having a coded statement about the efficiency technology (row). 

The second number measures the difference with all other reviews that do not have coded statements about 

the technology. Significance with 10% (*), 5% (**), and 1% (***) is estimated using t-tests for differences 

in means. 

18
 
 

Draft – Subject to Revision 

Table 9: Share of reviews with negative operational reviews conditional on efficiency technology 

using Tech Data 

Steering FeelCorneringAbilityGeneralDrivabilityGeneralHandlingAccelerationFeelAccelerationCapabilityGeneralAccelerationBrake FeelStoppingAbilityGeneralBrakingTire-RoadNoise 

Low Resistance Tires 

(N=31) 

0.23 

0.09 

0.13 

0.04 

0.16 

0.06 

0.13 

0.05 

0.06 

-0.01 

0.19 

0.04 

0.03 

0 

0.03 

-0.02 

0.10 

0.06 

0.03 

0.01 

0.03 

-0.04 

Diesel (N=38) 0.13 

-0.01 

0.00 

-.09*** 

0.00 

-.11*** 

0.00 

-.08*** 

0.03 

-0.05 

0.13 

-0.03 

0.00 

-.03*** 

0.00 

-.06*** 

0.03 

-0.01 

0.00 

-.02*** 

0.03 

-.05* 

Electronic Power 

Steering (N=532) 

0.16 

.05* 

0.09 

0.01 

0.10 

-0.01 

0.09 

.03* 

0.07 

-0.01 

0.18 

.07** 

0.03 

0.01 

0.06 

0.02 

0.05 

.03*** 

0.03 

.02** 

0.08 

0.03 

Full Electric (N=8) 0.13 

-0.02 

0.00 

-.09*** 

0.00 

-.1*** 

0.00 

-.08*** 

0.13 

0.05 

0.13 

-0.03 

0.00 

-.03*** 

0.00 

-.05*** 

0.00 

-.04*** 

0.13 

0.1 

0.00 

-.07*** 

GDI (N=424) 0.13 

-0.03 

0.08 

-0.02 

0.06 

-.1*** 

0.05 

-.07*** 

0.06 

-0.02 

0.12 

-.11*** 

0.02 

-.03* 

0.04 

-.04** 

0.03 

-0.01 

0.02 

-0.01 

0.06 

-.04* 

Hybrid (N=45) 0.20 

0.06 

0.09 

0 

0.22 

.13* 

0.07 

-0.01 

0.09 

0.02 

0.27 

.12* 

0.02 

-0.01 

0.22 

.18*** 

0.07 

0.03 

0.07 

0.05 

0.02 

-.05** 

Plug-In Hybrid 

Electric (N=17) 

0.06 

-0.09 

0.18 

0.09 

0.18 

0.08 

0.18 

0.1 

0.06 

-0.01 

0.18 

0.02 

0.00 

-.03*** 

0.00 

-.05*** 

0.06 

0.02 

0.00 

-.02*** 

0.06 

-0.01 

Cylinder Deactivation 

(N=58) 

0.14 

-0.01 

0.05 

-0.04 

0.05 

-.06* 

0.10 

0.03 

0.03 

-0.04 

0.07 

-.1*** 

0.00 

-.03*** 

0.03 

-0.02 

0.07 

0.04 

0.02 

-0.01 

0.09 

0.01 

Stop-Start (N=130) 0.14 

-0.01 

0.06 

-0.03 

0.04 

-.08*** 

0.03 

-.06*** 

0.08 

0.02 

0.08 

-.1*** 

0.00 

-.04*** 

0.03 

-0.03 

0.02 

-.03* 

0.01 

-.02* 

0.04 

-.04** 

Turbocharged 

(N=238) 

0.15 

0.01 

0.06 

-.03* 

0.07 

-.05** 

0.05 

-.04** 

0.08 

0.01 

0.11 

-.07** 

0.03 

-0.01 

0.03 

-.04** 

0.02 

-.02* 

0.03 

0 

0.05 

-0.03 

CVT (N=54) 0.22 

0.09 

0.17 

0.09 

0.26 

.17*** 

0.20 

.13** 

0.15 

.08* 

0.41 

.27*** 

0.06 

0.03 

0.06 

0 

0.09 

0.06 

0.02 

0 

0.07 

0 

DCT (N=67) 0.13 

-0.01 

0.06 

-0.03 

0.10 

0 

0.06 

-0.02 

0.09 

0.02 

0.13 

-0.03 

0.01 

-0.02 

0.03 

-0.03 

0.03 

-0.01 

0.04 

0.02 

0.12 

0.05 

High Speed 

Automatic (N=401) 

0.13 

-0.02 

0.09 

0.02 

0.08 

-.06** 

0.06 

-0.03 

0.05 

-.04** 

0.12 

-.09*** 

0.02 

-0.01 

0.05 

-0.01 

0.03 

-0.01 

0.01 

-.03** 

0.07 

-0.01 

The top number in each cell is the fraction of reviews with a negative coded statement about the 

operational characteristic (column) conditional on the presence of the efficiency technology (row) as 

reported in the matched Tech Data. The second number measures the difference with all other reviews that 

Tech Data report do not have the technology. Significance with 10% (*), 5% (**), and 1% (***) is estimated 

using t-tests for differences in means. 

19
 
 

 

 

 

Draft – Subject to Revision 

Table 9 Continued 

Wind Noise

Interior Noise

Powertrain

Noise

General Noise

Chassis

Vibration

Powertrain

Vibration

General

Vibration

Ride Comfort

Fuel Economy

Range

Charging 

Low Resistance Tires 

(N=31) 

0.03 

0 

0.03 

0.02 

0.19 

0.05 

0.06 

0 

0.00 

-.01** 

0.00 

-.01*** 

0.00 

-.02*** 

0.03 

-.13*** 

0.06 

-.1** 

0.03 

0.02 

0.10 

.1* 

Diesel (N=38) 0.03 

-0.01 

0.00 

-.02*** 

0.11 

-0.04 

0.05 

-0.01 

0.00 

-.01** 

0.03 

0.02 

0.00 

-.02*** 

0.03 

-.13*** 

0.08 

-.09* 

0.00 

-.01** 

0.00 

0* 

Electronic Power 

Steering (N=532) 

0.04 

.03** 

0.01 

-0.01 

0.16 

0.04 

0.07 

0.02 

0.01 

-0.01 

0.01 

0 

0.02 

0.01 

0.15 

-0.01 

0.14 

-.08** 

0.01 

0 

0.01 

.01* 

Full Electric (N=8) 0.00 

-.04*** 

0.00 

-.02*** 

0.00 

-.15*** 

0.00 

-.06*** 

0.00 

-.01** 

0.00 

-.01*** 

0.00 

-.02*** 

0.00 

-.15*** 

0.00 

-.16*** 

0.00 

-.01** 

0.13 

0.12 

GDI (N=424) 0.03 

-0.02 

0.01 

-0.01 

0.09 

-.13*** 

0.04 

-.05** 

0.00 

-0.01 

0.01 

-0.01 

0.02 

-0.01 

0.14 

-0.02 

0.11 

-.11*** 

0.00 

-0.01 

0.00 

-.01* 

Hybrid (N=45) 0.00 

-.04*** 

0.00 

-.02*** 

0.18 

0.03 

0.07 

0 

0.00 

-.01** 

0.00 

-.01*** 

0.00 

-.02*** 

0.11 

-0.04 

0.20 

0.04 

0.00 

-.01** 

0.00 

0* 

Plug-In Hybrid 

Electric (N=17) 

0.00 

-.04*** 

0.00 

-.02*** 

0.29 

0.15 

0.00 

-.07*** 

0.00 

-.01** 

0.00 

-.01*** 

0.00 

-.02*** 

0.06 

-0.1 

0.06 

-0.1 

0.24 

.23** 

0.12 

0.12 

Cylinder Deactivation 

(N=58) 

0.03 

0 

0.02 

0 

0.10 

-0.05 

0.05 

-0.01 

0.00 

-.01** 

0.02 

0.01 

0.00 

-.02*** 

0.17 

0.02 

0.07 

-.1*** 

0.00 

-.01** 

0.00 

0* 

Stop-Start (N=130) 0.02 

-.02* 

0.00 

-.02*** 

0.04 

-.13*** 

0.05 

-0.02 

0.00 

-.01** 

0.01 

0 

0.02 

-0.01 

0.15 

-0.01 

0.10 

-.07** 

0.01 

0 

0.00 

-.01* 

Turbocharged 

(N=238) 

0.01 

-.03*** 

0.00 

-.02** 

0.11 

-.05* 

0.05 

-0.03 

0.00 

-.01** 

0.01 

0 

0.03 

0.01 

0.12 

-.05* 

0.11 

-.08*** 

0.00 

-0.01 

0.00 

-.01* 

CVT (N=54) 0.07 

0.04 

0.02 

0 

0.39 

.26*** 

0.15 

.09* 

0.02 

0.01 

0.04 

0.03 

0.07 

0.06 

0.17 

0.01 

0.24 

0.09 

0.00 

-.01** 

0.00 

0* 

DCT (N=67) 0.01 

-0.02 

0.01 

0 

0.15 

0 

0.06 

0 

0.01 

0.01 

0.00 

-.01*** 

0.04 

0.03 

0.31 

.18*** 

0.09 

-.08** 

0.00 

-.01** 

0.00 

0* 

High Speed 

Automatic (N=401) 

0.03 

-0.02 

0.01 

0 

0.11 

-.08*** 

0.05 

-.03* 

0.01 

0 

0.01 

0 

0.01 

-0.01 

0.14 

-0.03 

0.17 

0.02 

0.00 

-0.01 

0.00 

-.01* 

The top number in each cell is the fraction of reviews with a negative coded statement about the 

operational characteristic (column) conditional on the presence of the efficiency technology (row) as 

reported in the matched Tech Data. The second number measures the difference with all other reviews that 

Tech Data reports do not have the technology. Significance with 10% (*), 5% (**), and 1% (***) is 

estimated using t-tests for differences in means. 

The descriptive statistics in Table 8 and Table 9 are essentially conditional sample means. 

Although it is tempting to make causal statements based on the differences, we cannot assume an 

absence of selection bias. For example, although the results suggest that vehicles with CVTs tend 

to have a higher percentage of negative reviews on acceleration capability, it could be that the 

same vehicles without CVTs would also generate negative acceleration reviews. In other words, 

we cannot rule out the possibility that CVTs have been implemented on vehicles that would have 

had, on average, worse acceleration scores anyway. If true, then we would not be able to attribute 

differences in the fraction of negative reviews by technology to the existence of the technology 

itself. 

20
 
 

 

 

 

 

 

 

Draft – Subject to Revision 

In order to reduce concerns about selection bias, we then estimated a series of linear 

probability models5 for each operational characteristic that include fixed effects for make, 

vehicle class, and website, as well as vehicle attributes from the linked tech data. Although we 

cannot rule out the existence of selection bias using this control strategy either, our assumption is 

that the fixed effects and vehicle controls generate improved approximations of the effects of 

these technologies. At a minimum, we can use the results to discuss the correlations between 

efficiency technologies and vehicle performance conditional on class, make, website and vehicle 

attributes. 

Regression results for each operational characteristic are presented in Appendix Table 

A1-Table A22. We estimate six specifications for each operational characteristic, all of which 

include fixed effects for make, vehicle class, and website. For the first two specifications, we 

used mentions of the technologies in the reviews as our source of the existence of the 

technologies on the vehicles; in the next four, we used the technology data. The regressions 

using the technology data are further divided between those that use only the data on the fuelsaving technologies, and those that include a set of additional vehicle attributes included in the 

technology data.6 Finally, these 3 sets of regressions (Coded Tech in Review; Tech Data; Tech 

Data plus Vehicle Attributes) are further divided into regressions where only one technology is 

included, and regressions where all the technologies are included simultaneously. 

This process gives six possibilities for a relationship between each operational 

characteristic and each technology. We provide one summary of these findings in Table 10, 

which shows, for each combination of an operational characteristic and a technology, whether 

any of the six regressions has a statistically significant coefficient on that relationship, and 

whether the sign of the effect is consistent across the significant results. A positive coefficient 

(“+” in Table 10) indicates that the presence of the technology is associated with an increase in 

the likelihood of a negative review on the characteristic – that is, a hidden cost. A negative 

coefficient (“-” in Table 10), in contrast, signals the possibility of a hidden benefit, a positive 

relationship between a technology and the characteristic.7 

5 As robustness checks, we ran the same sets of regressions using logit and probit specifications. We are 

still reviewing those results. 

6 Included vehicle attributes include horsepower, torque, number of cylinders, engine displacement, number 

of doors, length, width, height, wheelbase, footprint, and curb weight. 

7 For some technologies, it may be possible to use efficiency gains either to reduce GHG emissions or to 

enhance other vehicle characteristics, such as acceleration (e.g., Klier and Linn 2015). If so, then the hidden benefits 

may reflect a decision to implement technologies for purposes other than, or in addition to, GHG reduction. 

21
 
 

 

 

Draft – Subject to Revision 

Table 10: Sign and significance level of statistically significant results from linear probability 

model regressions that estimate the probability of negative operational characteristic reviews 

conditional on efficiency technology. Steering Feel Cornering Ability

General DrivabilityGeneral HandlingAcceleration FeelAcceleration CapabilityGeneral AccelerationBrake FeelStopping AbilityGeneral BrakingTire-Road Noise 

Active Air Dam -* 

Active Grille Shutters -*** -** -*** -*** -* 

Active Ride Height -** -*** +* 

Low Resistance Tires +** +** 

Electronic Power Steering +*** -*** -** +* +* 

Turbocharged -** m* -* 

GDI -*** -* -** -* -** -** 

Cylinder Deactivation +* -*** +* +* +*** 

Diesel -* -*** -*** -*** -** -** 

Hybrid -*** +** -* -** +*** -*** 

Plug-In Hybrid Electric -* -* -*** +* 

Full Electric -** +* -** -* 

Stop-Start +*** -*** -* 

High Speed Automatic -** +* -** -*** -** -** -* +* 

CVT +*** +** +* +* +*** -* +** -** 

DCT +* +** 

Elec Assist / Low Drag Brakes 

Lighting-LED -*** -*** -** 

Mass Reduction -* -** 

Passive Aerodynamics -** -* 

Non-empty table cells indicate that a statistically significant result was obtained in one of the LPM 

regressions that estimate the probability of a negative review for the column variable conditional on 

technology given by the row. The actual regression results are presented in Appendix Table A1-Table 

A22. A “+” indicates a consistent positive effect across regressions with significant results for the 

efficiency technology, i.e. the technology is associated with increased probability of a negative review. 

Conversely, a “-” indicates a consistent negative effect across regressions with significant results for the 

efficiency technology, i.e. the technology is associated with a decreased probability of a negative review. 

An “m” indicates mixed positive and negative results across the significant estimates. Asterisks indicate 

the level of the most significant result obtained across the different LPM estimates: 10% (*), 5% (**), and 

1% (***) levels. 

22
 
 

 

 

 

 

Draft – Subject to Revision 

Table 10 Continued 

Wind NoiseInterior NoisePowertrain NoiseGeneral NoiseChassis VibrationPowertrain VibrationGeneral VibrationRide ComfortFuel EconomyRangeCharging 

Active Air Dam 

Active Grille Shutters +** -*** 

Active Ride Height -*** -** 

Low Resistance Tires -* -*** -*** +* 

Electronic Power Steering -** -* +* -** -** 

Turbocharged -** -** 

GDI -** -* -** -* -*** -* 

Cylinder Deactivation -** -* -*** +* 

Diesel -* -*** -*** 

Hybrid -** -** -* 

Plug-In Hybrid Electric +*** +* -** -*** +*** 

Full Electric -** -*** -** -*** -*** 

Stop-Start -*** -** -* 

High Speed Automatic -*** -* -* 

CVT +** -* +*** -* -** 

DCT -** -* +*** 

Elec Assist / Low Drag Brakes -** -* -** 

Lighting-LED -*** +* -*** +* -* 

Mass Reduction -* -** -* 

Passive Aerodynamics -* -*** 

Non-empty table cells indicate that a statistically significant result was obtained in one of the 

LPM regressions that estimate the probability of a negative review for the column variable conditional on 

technology given by the row. The actual regression results are presented in Appendix Table A1-Table 

A22. A “+” indicates a consistent positive effect across regressions with significant results for the 

efficiency technology, i.e. the technology is associated with increased probability of a negative review. 

Conversely, a “-” indicates a consistent negative effect across regressions with significant results for the 

efficiency technology, i.e. the technology is associated with a decreased probability of a negative review. 

An “m” indicates mixed positive and negative results across the significant estimates. Asterisks indicate 

the level of the most significant result obtained across the different LPM estimates: 10% (*), 5% (**), and 

1% (***) levels. 

23
 
 

 

 

 

 

 

Draft – Subject to Revision 

Perhaps a first observation on the table is that about two-thirds of 440 cells (20 

technologies by 22 characteristics) are blank: for a majority of the technology-characteristic 

combinations, across all specifications, there is no correlation between the technology and the 

characteristic. In some cases, technologies are not expected to affect some of the characteristics: 

for instance, LED lights are not expected to affect noise, acceleration, or brake feel. In other 

cases, as previously discussed, this observation may be due to selection bias. Manufacturers 

choose both how to design vehicles for operational characteristics and what technologies to use 

in the vehicles, and other factors not included in the regressions may be correlated with both the 

characteristics and the technologies. As a result, the regression may not fully control for omitted 

factors. Hence, we describe all these results in terms of correlation rather than causality. 

For most cases where a correlation is identified, the technology is associated with a lower 

probability of a negative review on the operational characteristic. Thirty-seven table cells (8.4 

percent) have a significant positive (bad) result, while 108 cells (24.5 percent) have a significant 

negative (good) result, and only 1 (0.2 percent) is mixed. In addition, the presence of a 

technology may be correlated with negative effects on some characteristics but positive effects 

on others: looking across the rows, all but 3 technologies (CVT, DCT, and cylinder 

deactivation) have at least as many negative (good) significant effects as positive (bad) effects; 7 

technologies (active air dam, turbocharged, GDI, diesel, electronic assist/low drag brakes, mass 

reduction, and passive aerodynamics) show only negative (good) significant effects. 

We consider Table 10 to provide a highly sensitive measure of the possibility of hidden 

costs: it does not consider consistency across specifications, but rather shows any indication of a 

relationship between an operational characteristic and a technology. Table 11 provides the 

number of significant coefficients in the regressions based on consistent significance across 

specifications. As it shows, statistical significance is not very robust in these regressions: the 

number of significant coefficients drops rapidly as consistency across more regressions is sought. 

In fact, only 2 cells have significant results across all 6 specifications: diesel has a negative 

association with a negative rating for general drivability, and CVT has a positive association 

with a negative rating for acceleration capability. As discussed above, these sensitivities may 

reflect correlations of observed variables with unobserved variables. 

Table 11: Number of Significant Coefficients Conditional on the Number of Specifications with 

Significance (out of 440 possible coefficients) 

Number of Significant Estimates 1 2 3 4 5 6 

Positive Correlations 37 21 12 7 2 1 

Negative Correlations 108 71 24 17 4 1 

Mixed Correlations 1 1 0 0 0 0 

Total 146 93 36 24 6 2 

The analyses above have focused on negative evaluations of operational characteristics – hidden 

costs – as the key variables of interest. It is possible that some of these negative evaluations of 

characteristics are due, not to the existence of the technology, but rather to the way that the 

technology is implemented. Perhaps, for instance, a badly implemented CVT is associated with 

negative acceleration capability, but a well implemented CVT may not have this effect. Table 12 

explores this question by considering the relationship between the rating of a technology with the 

24
 
 

 

 

 

 

 

Draft – Subject to Revision 

ratings of the operational characteristics.8 Each cell summarizes 22 regressions of each 

operational characteristic on a technology, where the dependent variable is again a dummy 

variable for a negative review of each operational characteristic. The regressions use the coded 

review data to control for “any mention” of all other technologies as well as make, website, and 

class fixed effects. The table reports estimates for 4 separate groups of regressions with the only 

differences being the rating represented by the dummy variable for the row technology. For 

instance, the presence of CVTs (All Mentions) is associated with a negative rating on four 

operational characteristics. The next column, Negative Tech, shows that negative evaluations of 

CVTs are associated with negative ratings for seven operational characteristics. In other words, 

there are more negative evaluations of operational characteristics when CVTs are rated 

negatively than when they are merely present. This pattern generalizes: technologies that are 

evaluated negatively are more likely to be associated with negative evaluations of operational 

characteristics than when the technologies are evaluated neutrally or positively, or are just 

present. It is possible that poor implementation may be contributing to negative evaluations of 

operational characteristics; positive or neutral evaluations of the technologies do not have the 

same adverse effects on operational characteristics. 

8 This analysis uses only the content analysis data, because it contains evaluations of the technologies. The 

technology database does not include evaluations of the technologies. This analysis uses the regressions with all 

technologies included. 

25
 
 

 

 

 

Draft – Subject to Revision 

Table 12: Relationship of Rating of Technologies with Rating of Operational Characteristics 

All 

Mentions 

Negative 

Tech 

Neutral 

Tech 

Positive 

Tech 

Active Air Dam 

Active Grille Shutters 

Active Ride Height 

Low Resistance Tires 1 2 

Electronic Power Steering 1 1 

Turbocharged 2 

GDI 1 

Cylinder Deactivation 2 1 

Diesel 2 

Hybrid 3 

Plug-In Hybrid Electric 1 1 

Full Electric 1 

Stop-Start 

High Speed Automatic Transmission 7 

CVT 4 7 

DCT 1 

Elec Assist Or Low Drag Brakes 3 

Lighting-LED 2 

Mass Reduction 1 

Passive Aerodynamics 1 

Each row summarizes 4 groups of regressions, where each operational characteristic is regressed on a dummy 

variable for the presence of a negative, neutral, positive, or any mention (specified by the column) of the row 

technology. The dependent variables are again dummy variables for negative reviews of each operational 

characteristic. The regressions use the coded review data to control for “any mention” of all other technologies as 

well as make, website, and class fixed effects. 

In sum, our analyses find scant consistent evidence of hidden costs of emissions-reducing 

technologies. Each technology is reviewed positively more often than it is reviewed negatively; 

this finding suggests that implementation of the technologies, and not just the technologies 

themselves, affects the existence of hidden costs. Correlations between the existence of the 

technologies and operational characteristics often suggest that the technologies reduce the 

probability of negative reviews of the characteristics, and are not robust to alternative 

specifications. Negative evaluations of operational characteristics appear to be more common 

when the technologies are evaluated negatively than when they are merely present, another 

suggestion that poor implementation may be the primary source of hidden costs. 

26
 
 

 

 

 

Draft – Subject to Revision 

Potential Qualifications of this Analysis 

Content analysis as a method involves some degree of subjectivity; two readers of the 

same review may come to different conclusions about the reviewer’s responses. We believe this 

concern is unlikely to be significant. First, as noted above, we conducted significant training of 

the coders, including testing for (and achieving) inter-coder reliability throughout the coding 

process. Secondly, auto reviewers have opinions, and are not expected to be shy or misleading 

about their views; although their language may be colorful, the sentiment is generally clear. We 

believe the data to be of high quality. 

A notable characteristic of this work is that the analysis captures the technologies 

mentioned in auto reviews. One result is that biases in the data may arise because the counts of 

reviews for models are not proportional to vehicle sales. On the other hand, the proportions of 

reviews by make are similar to the proportions of vehicles offered for sale by make; this 

observation suggests that the reviews may be more representative of offerings. The data suggest 

that luxury vehicles are reviewed more than their representation in vehicle sales. In addition, it 

seems plausible that auto reviewers are more likely to test-drive vehicles that have undergone a 

significant redesign. Because redesigned vehicles are more likely to incorporate new 

technologies than vehicles that have not been redesigned, the data may over-represent the 

presence of these new technologies in the MY 2014 market. They may also emphasize the status 

of the new technologies; given the positive nature of the response, it suggests that automakers are 

generally doing well with these technologies, and it is reasonable to think that they will only do 

better in the future with them. 

This study relies on the opinions of professional auto reviewers. People who buy new 

vehicles may differ in their responses to these new technologies; if the public tends to be harsher 

critics than the reviewers, then these results may understate negative consumer response. As 

mentioned above, though, we expect professional auto reviewers, as experts, to be aware of 

vehicle characteristics and technologies more than the general public. If so, then this study may 

underestimate neutral or positive responses from the general public. 

As discussed above, our data are not sufficient to identify causality for the effects of the 

technologies on vehicles’ operational characteristics. It is possible that some technologies show 

adverse (or beneficial) effects on operational characteristics that are generated in part from 

selection bias. The ideal experiment would be to compare reviews from vehicles with a given 

technology to reviews from otherwise identical vehicles without the technology. This is 

generally not possible. Although our strategy controls for important fixed effects and vehicle 

attributes, our results may still be vulnerable to selection bias. However, even at the level of 

correlation, we find fewer signs of adverse effects from the technologies than neutral or 

beneficial effects. 

The reviewers’ comments are based on test drives of the vehicles. As a result, they are 

not designed to look for problems that might arise over longer time horizons, such as with 

reliability or maintenance. This study covered new MY 2014 vehicles; it will take several years 

before these problems, if any, come to light. 

Conclusion 

The energy paradox exists if there are technologies whose present net value is positive for 

consumers, even taking into account potential hidden costs of the technologies. Engineering 

analyses of light-duty vehicles suggest that a number of fuel-saving technologies have positive 

present net values for consumers. This study investigates whether these technologies have 

27
 
 

 

 

 

 

 

 

 

Draft – Subject to Revision 

hidden costs, by examining professional auto reviewers’ responses to these technologies in MY 

2014 vehicles. For the technologies included in the study – the primary technologies expected to 

be used to reduce vehicle GHG and fuel consumption to meet EPA and DOT standards – we find 

scant evidence of hidden costs. For all the technologies, positive mentions outweigh negative 

mentions; indeed, negative mentions constitute less than 20 percent of the total. Though we are 

unable to demonstrate causality or robustness, we find that the technologies are more likely to be 

associated with reducing negative reviews of operational characteristics than with increasing 

them. Some evidence suggests that, rather than hidden costs being inherent in the technologies, 

the quality of the implementation of the technologies may affect vehicle quality. If so, it is likely 

that implementation problems are temporary: automakers appear capable of good 

implementation of any of the technologies, and they are likely to address concerns as they arise. 

We do not find evidence, then, that hidden costs provide an explanation for the energy paradox 

in MY 2014 light-duty vehicles. 

28
 
 

 

 

 

 

 

 

 

 

 

 

 

Draft – Subject to Revision 

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Appendix Tables 

Table A1: "Steering feel" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.07 -0.02 

(0.07) (0.07) 

Active Grille 

Shutters 

-0.34*** -0.22** 

(0.10) (0.09) 

Active Ride Height -0.18** -0.15* 

(0.08) (0.08) 

Low Resistance 

Tires 

0.09 0.04 

(0.11) (0.11) 

0.11 0.11 

(0.09) (0.09) 

0.16 0.18 

(0.11) (0.11) 

Electronic Power 

Steering 

0.17*** 0.17*** 

(0.03) (0.04) 

-0.00 0.00 

(0.04) (0.05) 

-0.07 -0.06 

(0.05) (0.05) 

Turbocharged -0.00 0.00 

(0.03) (0.03) 

0.06 0.09 

(0.04) (0.05) 

0.06 -0.00 

(0.07) (0.08) 

GDI -0.03 -0.06 

(0.05) (0.05) 

-0.01 -0.05 

(0.04) (0.05) 

-0.04 -0.06 

(0.05) (0.06) 

Cylinder 

Deactivation 

0.04 0.06 

(0.09) (0.10) 

0.06 0.08 

(0.07) (0.07) 

0.12* 0.11 

(0.07) (0.07) 

Diesel -0.07 -0.02 

(0.05) (0.05) 

-0.02 -0.04 

(0.07) (0.08) 

-0.19* -0.22* 

(0.11) (0.12) 

Hybrid 0.01 -0.06 

(0.05) (0.05) 

0.03 0.02 

(0.06) (0.07) 

-0.15*** -0.21*** 

(0.05) (0.08) 

Plug-In Hybrid 

Electric 

-0.04 -0.06 

(0.07) (0.07) 

-0.12 -0.14* 

(0.07) (0.08) 

-0.05 -0.20 

(0.11) (0.17) 

Full Electric 0.03 0.03 

(0.08) (0.09) 

0.08 0.02 

(0.12) (0.12) 

0.00 0.00 

(.) (.) 

Stop-Start 0.03 0.03 

(0.06) (0.06) 

0.02 0.03 

(0.06) (0.06) 

0.00 -0.01 

(0.06) (0.06) 

High Speed 

Automatic 

-0.06** -0.07** 

(0.03) (0.03) 

-0.05 -0.04 

(0.04) (0.05) 

-0.04 -0.02 

(0.05) (0.05) 

CVT 0.07 0.06 

(0.06) (0.06) 

0.08 0.06 

(0.07) (0.08) 

0.08 0.00 

(0.07) (0.08) 

DCT 0.05 0.03 

(0.06) (0.06) 

0.03 0.01 

(0.05) (0.06) 

0.08 0.05 

(0.06) (0.07) 

Elec Assist / Low 

Drag Brakes 

0.08 0.05 

(0.17) (0.15) 

Lighting-LED -0.01 -0.02 

(0.11) (0.11) 

Mass Reduction -0.03 -0.05 

(0.04) (0.04) 

Passive 

Aerodynamics 

-0.05 -0.03 

(0.06) (0.05) 

Observations 

Adj-R2 

1003 

0.09 

718 

0.06 

660 

0.05 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Steering Feel” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

32
 
 

 

Draft – Subject to Revision 

Table A2: "Cornering ability" negative review linear probability model regressions on efficiency 

technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.08 -0.09 

(0.10) (0.10) 

Active Grille 

Shutters 

-0.19** -0.18** 

(0.08) (0.09) 

Active Ride Height -0.03 -0.02 

(0.04) (0.05) 

Low Resistance 

Tires 

0.25** 0.28** 

(0.12) (0.13) 

-0.01 -0.06 

(0.07) (0.08) 

0.05 -0.02 

(0.10) (0.10) 

Electronic Power 

Steering 

0.02 0.02 

(0.03) (0.03) 

-0.05 -0.06 

(0.03) (0.04) 

-0.06 -0.06 

(0.04) (0.05) 

Turbocharged -0.02 -0.01 

(0.03) (0.03) 

-0.03 -0.00 

(0.04) (0.05) 

0.00 -0.01 

(0.06) (0.07) 

GDI -0.07*** -0.06** 

(0.02) (0.03) 

-0.01 0.00 

(0.04) (0.05) 

-0.03 -0.03 

(0.04) (0.05) 

Cylinder 

Deactivation 

-0.12*** -0.09** 

(0.04) (0.04) 

-0.00 -0.03 

(0.04) (0.04) 

-0.00 -0.01 

(0.05) (0.05) 

Diesel -0.03 -0.01 

(0.04) (0.04) 

-0.10*** -0.13*** 

(0.03) (0.05) 

-0.10 -0.12 

(0.06) (0.09) 

Hybrid -0.03 -0.05 

(0.04) (0.05) 

-0.03 0.05 

(0.05) (0.05) 

-0.01 0.07 

(0.07) (0.08) 

Plug-In Hybrid 

Electric 

0.05 0.05 

(0.08) (0.08) 

0.09 0.15 

(0.12) (0.12) 

0.02 0.01 

(0.11) (0.15) 

Full Electric 0.00 -0.10 

(0.06) (0.07) 

-0.05 0.02 

(0.04) (0.06) 

0.00 0.00 

(.) (.) 

Stop-Start -0.05 -0.04 

(0.04) (0.04) 

0.01 0.03 

(0.05) (0.05) 

0.07 0.07 

(0.05) (0.05) 

High Speed 

Automatic 

-0.03 -0.01 

(0.02) (0.02) 

0.02 0.06* 

(0.03) (0.03) 

0.01 0.06 

(0.04) (0.04) 

CVT 0.05 0.06 

(0.04) (0.04) 

0.12** 0.18*** 

(0.06) (0.06) 

0.16** 0.19*** 

(0.06) (0.06) 

DCT 0.02 0.03 

(0.04) (0.05) 

-0.01 0.01 

(0.04) (0.05) 

0.01 0.04 

(0.05) (0.05) 

Elec Assist / Low 

Drag Brakes 

-0.02 -0.04 

(0.03) (0.05) 

Lighting-LED -0.09 -0.09 

(0.10) (0.10) 

Mass Reduction -0.00 -0.01 

(0.03) (0.03) 

Passive 

Aerodynamics 

-0.04 -0.05 

(0.05) (0.05) 

Observations 

Adj-R2 

1003 

0.08 

718 

0.03 

660 

0.05 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Cornering Ability” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on 

all technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

33
 
 

 

Draft – Subject to Revision 

Table A3: "General drivability" negative review linear probability model regressions on efficiency 

technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.03 -0.03 

(0.08) (0.08) 

Active Grille 

Shutters 

-0.06 -0.04 

(0.06) (0.06) 

Active Ride Height -0.03 0.00 

(0.05) (0.05) 

Low Resistance 

Tires 

0.12 0.12 

(0.12) (0.12) 

0.14* 0.10 

(0.08) (0.10) 

0.22** 0.18 

(0.11) (0.12) 

Electronic Power 

Steering 

-0.04 -0.04* 

(0.02) (0.02) 

-0.04 -0.06 

(0.04) (0.05) 

-0.11** -0.14*** 

(0.05) (0.05) 

Turbocharged -0.01 0.01 

(0.03) (0.03) 

-0.03 0.02 

(0.04) (0.05) 

-0.03 -0.06 

(0.07) (0.08) 

GDI 0.01 0.04 

(0.04) (0.05) 

-0.06 -0.02 

(0.04) (0.04) 

-0.03 0.01 

(0.05) (0.05) 

Cylinder 

Deactivation 

-0.06 -0.08 

(0.06) (0.07) 

-0.01 -0.01 

(0.04) (0.04) 

-0.02 -0.05 

(0.04) (0.04) 

Diesel -0.06* -0.06* 

(0.03) (0.03) 

-0.10*** -0.10** 

(0.03) (0.04) 

-0.17** -0.25*** 

(0.09) (0.10) 

Hybrid 0.09 0.07 

(0.06) (0.06) 

0.12* 0.15** 

(0.06) (0.07) 

0.08 0.01 

(0.10) (0.12) 

Plug-In Hybrid 

Electric 

0.02 0.01 

(0.08) (0.09) 

0.15 0.15 

(0.11) (0.13) 

-0.11 -0.31* 

(0.12) (0.16) 

Full Electric 0.10 0.04 

(0.10) (0.09) 

-0.06 -0.09 

(0.05) (0.08) 

0.00 0.00 

(.) (.) 

Stop-Start -0.04 -0.03 

(0.05) (0.05) 

-0.05 -0.03 

(0.05) (0.05) 

-0.00 -0.02 

(0.05) (0.05) 

High Speed 

Automatic 

-0.05** -0.03 

(0.02) (0.02) 

-0.04 0.02 

(0.03) (0.03) 

-0.02 0.01 

(0.03) (0.04) 

CVT 0.14** 0.13** 

(0.06) (0.06) 

0.07 0.12 

(0.07) (0.08) 

0.06 0.03 

(0.08) (0.08) 

DCT -0.05 -0.05 

(0.04) (0.04) 

-0.00 -0.01 

(0.05) (0.05) 

-0.03 -0.04 

(0.05) (0.06) 

Elec Assist / Low 

Drag Brakes 

-0.04 -0.05 

(0.03) (0.05) 

Lighting-LED -0.03 -0.05 

(0.10) (0.11) 

Mass Reduction -0.05* -0.04 

(0.03) (0.03) 

Passive 

Aerodynamics 

-0.09** -0.06 

(0.04) (0.04) 

Observations 

Adj-R2 

1003 

0.09 

718 

0.10 

660 

0.12 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “General Drivability” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on 

all technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

34
 
 

 

Draft – Subject to Revision 

Table A4: "General handling" negative review linear probability model regressions on efficiency 

technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam 0.27 0.25 

(0.18) (0.18) 

Active Grille 

Shutters 

-0.00 -0.03 

(0.04) (0.04) 

Active Ride Height -0.03 0.02 

(0.05) (0.04) 

Low Resistance 

Tires 

0.03 0.05 

(0.08) (0.08) 

0.01 -0.03 

(0.07) (0.08) 

0.08 0.05 

(0.10) (0.10) 

Electronic Power 

Steering 

-0.02 -0.01 

(0.02) (0.02) 

-0.03 -0.03 

(0.03) (0.04) 

-0.06 -0.05 

(0.04) (0.05) 

Turbocharged -0.06** -0.05** 

(0.02) (0.02) 

-0.03 0.00 

(0.03) (0.04) 

0.03 0.01 

(0.07) (0.08) 

GDI -0.02 -0.01 

(0.03) (0.03) 

-0.06* -0.07 

(0.03) (0.04) 

-0.05 -0.07 

(0.04) (0.05) 

Cylinder 

Deactivation 

-0.04 -0.04 

(0.05) (0.06) 

0.10* 0.11* 

(0.06) (0.06) 

0.10 0.12* 

(0.06) (0.07) 

Diesel -0.09*** -0.07*** 

(0.03) (0.03) 

-0.07** -0.03 

(0.03) (0.04) 

-0.06 -0.03 

(0.06) (0.07) 

Hybrid -0.02 -0.03 

(0.04) (0.04) 

-0.07 -0.05 

(0.05) (0.06) 

-0.07* -0.08 

(0.04) (0.05) 

Plug-In Hybrid 

Electric 

0.06 0.07 

(0.07) (0.09) 

0.11 0.06 

(0.11) (0.12) 

0.09 -0.00 

(0.07) (0.11) 

Full Electric -0.01 -0.06 

(0.06) (0.06) 

-0.10** -0.12* 

(0.05) (0.07) 

0.00 0.00 

(.) (.) 

Stop-Start -0.05 -0.05 

(0.04) (0.04) 

-0.05 -0.04 

(0.04) (0.04) 

-0.01 -0.00 

(0.04) (0.04) 

High Speed 

Automatic 

-0.01 0.00 

(0.02) (0.02) 

-0.03 -0.03 

(0.03) (0.03) 

-0.04 -0.03 

(0.03) (0.04) 

CVT 0.03 0.03 

(0.05) (0.05) 

0.11* 0.10 

(0.07) (0.07) 

0.10 0.07 

(0.07) (0.08) 

DCT 0.06 0.05 

(0.05) (0.05) 

-0.01 -0.04 

(0.04) (0.04) 

0.02 -0.02 

(0.05) (0.05) 

Elec Assist / Low 

Drag Brakes 

0.01 0.01 

(0.04) (0.04) 

Lighting-LED -0.00 -0.00 

(0.09) (0.10) 

Mass Reduction -0.01 -0.01 

(0.03) (0.03) 

Passive 

Aerodynamics 

-0.04 -0.05 

(0.04) (0.04) 

Observations 

Adj-R2 

1003 

0.09 

718 

0.04 

660 

0.04 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “General Handling” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on 

all technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

35
 
 

 

Draft – Subject to Revision 

Table A5: "Acceleration feel" negative review linear probability model regressions on efficiency 

technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam 0.02 0.03 

(0.02) (0.03) 

Active Grille 

Shutters 

-0.23*** -0.20** 

(0.09) (0.09) 

Active Ride Height -0.17*** -0.13** 

(0.06) (0.06) 

Low Resistance 

Tires 

0.15 0.09 

(0.12) (0.10) 

-0.02 -0.05 

(0.06) (0.06) 

-0.05 -0.12 

(0.08) (0.09) 

Electronic Power 

Steering 

0.01 0.00 

(0.02) (0.02) 

-0.07** -0.07* 

(0.03) (0.04) 

-0.04 -0.03 

(0.03) (0.04) 

Turbocharged -0.01 0.01 

(0.03) (0.03) 

0.00 0.02 

(0.04) (0.04) 

-0.03 -0.06 

(0.05) (0.05) 

GDI -0.00 0.01 

(0.03) (0.04) 

-0.02 -0.00 

(0.03) (0.04) 

-0.06 -0.07 

(0.04) (0.04) 

Cylinder 

Deactivation 

-0.01 -0.01 

(0.03) (0.04) 

-0.01 -0.02 

(0.03) (0.03) 

-0.01 0.01 

(0.03) (0.04) 

Diesel -0.08** -0.06* 

(0.03) (0.04) 

-0.08** -0.10* 

(0.04) (0.05) 

-0.10 -0.11 

(0.08) (0.09) 

Hybrid 0.07 0.04 

(0.05) (0.05) 

0.02 0.02 

(0.05) (0.05) 

0.07 0.05 

(0.10) (0.10) 

Plug-In Hybrid 

Electric 

-0.07*** -0.12*** 

(0.02) (0.04) 

-0.01 0.00 

(0.08) (0.09) 

-0.26* -0.38** 

(0.15) (0.16) 

Full Electric 0.16 0.15* 

(0.10) (0.09) 

0.03 0.06 

(0.12) (0.13) 

0.00 0.00 

(.) (.) 

Stop-Start -0.02 -0.01 

(0.05) (0.05) 

0.05 0.09 

(0.05) (0.05) 

0.14*** 0.14*** 

(0.05) (0.05) 

High Speed 

Automatic 

-0.05*** -0.03* 

(0.02) (0.02) 

-0.05* -0.04 

(0.03) (0.03) 

-0.06* -0.06 

(0.04) (0.04) 

CVT 0.08* 0.07 

(0.05) (0.05) 

0.02 0.04 

(0.06) (0.07) 

0.04 0.05 

(0.06) (0.07) 

DCT 0.01 -0.01 

(0.04) (0.04) 

0.05 0.01 

(0.05) (0.06) 

0.01 -0.01 

(0.06) (0.06) 

Elec Assist / Low 

Drag Brakes 

0.13 0.09 

(0.15) (0.13) 

Lighting-LED -0.16*** -0.17*** 

(0.04) (0.04) 

Mass Reduction -0.04** -0.04** 

(0.02) (0.02) 

Passive 

Aerodynamics 

-0.06* -0.03 

(0.03) (0.03) 

Observations 

Adj-R2 

1003 

0.08 

718 

0.01 

660 

0.03 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Acceleration Feel” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on 

all technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

36
 
 

 

Draft – Subject to Revision 

Table A6: "Acceleration capability" negative review linear probability model regressions on efficiency 

technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.15* -0.15 

(0.09) (0.10) 

Active Grille 

Shutters 

-0.22*** -0.20** 

(0.08) (0.09) 

Active Ride Height 0.23 0.20 

(0.29) (0.31) 

Low Resistance 

Tires 

0.02 0.02 

(0.12) (0.12) 

0.01 -0.12 

(0.09) (0.10) 

-0.03 -0.15 

(0.11) (0.12) 

Electronic Power 

Steering 

-0.02 -0.01 

(0.03) (0.03) 

0.07* 0.08 

(0.04) (0.05) 

0.02 0.04 

(0.05) (0.06) 

Turbocharged -0.01 -0.01 

(0.03) (0.03) 

-0.05 -0.01 

(0.04) (0.05) 

-0.02 -0.05 

(0.09) (0.10) 

GDI 0.03 0.05 

(0.05) (0.05) 

-0.11** -0.13** 

(0.04) (0.06) 

-0.11* -0.13** 

(0.05) (0.06) 

Cylinder 

Deactivation 

0.01 -0.00 

(0.07) (0.07) 

-0.03 0.01 

(0.06) (0.07) 

-0.03 0.01 

(0.07) (0.07) 

Diesel 0.04 0.05 

(0.07) (0.07) 

0.02 0.10 

(0.07) (0.08) 

-0.07 -0.05 

(0.11) (0.13) 

Hybrid -0.02 -0.05 

(0.05) (0.06) 

0.07 0.08 

(0.07) (0.08) 

0.04 0.05 

(0.11) (0.13) 

Plug-In Hybrid 

Electric 

0.03 0.02 

(0.09) (0.10) 

0.00 -0.05 

(0.10) (0.12) 

0.03 -0.18 

(0.11) (0.18) 

Full Electric 0.08 0.05 

(0.11) (0.11) 

-0.07 -0.12 

(0.13) (0.15) 

0.00 0.00 

(.) (.) 

Stop-Start -0.11*** -0.10** 

(0.04) (0.04) 

-0.09* -0.08 

(0.05) (0.05) 

-0.15** -0.13** 

(0.06) (0.06) 

High Speed 

Automatic 

-0.05* -0.03 

(0.03) (0.03) 

-0.10** -0.06 

(0.04) (0.05) 

-0.11** -0.08 

(0.05) (0.05) 

CVT 0.21*** 0.21*** 

(0.06) (0.07) 

0.23*** 0.26*** 

(0.09) (0.09) 

0.18** 0.20** 

(0.09) (0.10) 

DCT 0.05 0.06 

(0.06) (0.06) 

-0.02 -0.01 

(0.06) (0.07) 

0.04 0.02 

(0.07) (0.08) 

Elec Assist / Low 

Drag Brakes 

-0.01 0.01 

(0.17) (0.16) 

Lighting-LED -0.09 -0.13 

(0.09) (0.10) 

Mass Reduction -0.02 -0.01 

(0.04) (0.04) 

Passive 

Aerodynamics 

-0.08 -0.07 

(0.05) (0.05) 

Observations 

Adj-R2 

1003 

0.09 

718 

0.10 

660 

0.10 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Acceleration Capability” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions 

on all technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported 

in parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

37
 
 

 

Draft – Subject to Revision 

Table A7: "General acceleration" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.07 -0.07 

(0.06) (0.06) 

Active Grille 

Shutters 

-0.08 -0.09* 

(0.05) (0.05) 

Active Ride Height 0.02* 0.02 

(0.01) (0.02) 

Low Resistance 

Tires 

0.06 0.05 

(0.06) (0.07) 

-0.04 0.01 

(0.04) (0.05) 

-0.03 0.01 

(0.07) (0.07) 

Electronic Power 

Steering 

-0.00 -0.00 

(0.01) (0.01) 

0.02 0.02 

(0.02) (0.02) 

0.03 0.04 

(0.02) (0.02) 

Turbocharged -0.02* -0.02 

(0.01) (0.01) 

0.04* 0.04 

(0.02) (0.03) 

0.04 0.05 

(0.04) (0.04) 

GDI -0.01 -0.02* 

(0.01) (0.01) 

0.01 -0.02 

(0.02) (0.03) 

-0.03 -0.04 

(0.03) (0.03) 

Cylinder 

Deactivation 

0.01 0.02* 

(0.01) (0.01) 

-0.02 -0.02 

(0.01) (0.02) 

-0.02 -0.01 

(0.02) (0.02) 

Diesel 0.03 0.03 

(0.02) (0.02) 

0.02 0.01 

(0.01) (0.02) 

0.06 0.06 

(0.04) (0.05) 

Hybrid -0.00 -0.01 

(0.02) (0.02) 

-0.03 -0.05 

(0.02) (0.03) 

-0.06** -0.07 

(0.03) (0.05) 

Plug-In Hybrid 

Electric 

0.04 0.03 

(0.06) (0.04) 

-0.03 -0.05 

(0.02) (0.04) 

-0.03 0.03 

(0.05) (0.06) 

Full Electric 0.03 0.01 

(0.07) (0.07) 

-0.08** -0.10 

(0.04) (0.06) 

0.00 0.00 

(.) (.) 

Stop-Start 0.02 0.02 

(0.02) (0.02) 

-0.04 -0.06* 

(0.03) (0.03) 

-0.05 -0.04 

(0.04) (0.04) 

High Speed 

Automatic 

-0.01 -0.01 

(0.01) (0.01) 

0.03 0.01 

(0.03) (0.03) 

0.04 0.02 

(0.03) (0.04) 

CVT -0.04 -0.04 

(0.03) (0.03) 

-0.05 -0.06 

(0.04) (0.04) 

-0.04 -0.04 

(0.04) (0.04) 

DCT 0.01 0.01 

(0.02) (0.02) 

-0.01 -0.02 

(0.03) (0.03) 

-0.01 -0.01 

(0.03) (0.03) 

Elec Assist / Low 

Drag Brakes 

-0.01 -0.02 

(0.01) (0.02) 

Lighting-LED -0.02 -0.01 

(0.02) (0.02) 

Mass Reduction 0.00 0.00 

(0.02) (0.02) 

Passive 

Aerodynamics 

-0.01 -0.01 

(0.01) (0.01) 

Observations 

Adj-R2 

1003 

0.03 

718 

0.04 

660 

0.06 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “General Acceleration” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions 

on all technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported 

in parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

38
 
 

 

Draft – Subject to Revision 

Table A8: "Brake feel" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam 0.01 0.03 

(0.01) (0.02) 

Active Grille 

Shutters 

-0.03 -0.03 

(0.04) (0.05) 

Active Ride Height -0.02 -0.01 

(0.03) (0.04) 

Low Resistance 

Tires 

0.02 -0.00 

(0.07) (0.07) 

-0.01 -0.01 

(0.06) (0.06) 

0.01 -0.01 

(0.04) (0.04) 

Electronic Power 

Steering 

0.02 0.02 

(0.02) (0.02) 

0.01 0.00 

(0.03) (0.03) 

-0.00 -0.03 

(0.03) (0.03) 

Turbocharged -0.02 -0.01 

(0.02) (0.02) 

-0.04* -0.03 

(0.02) (0.03) 

-0.06 -0.07 

(0.05) (0.06) 

GDI -0.00 -0.01 

(0.02) (0.02) 

-0.02 0.00 

(0.02) (0.03) 

0.00 0.02 

(0.03) (0.03) 

Cylinder 

Deactivation 

0.01 0.01 

(0.05) (0.05) 

-0.03 -0.02 

(0.04) (0.05) 

0.01 -0.01 

(0.03) (0.04) 

Diesel -0.02 -0.01 

(0.03) (0.03) 

-0.04** -0.04 

(0.02) (0.03) 

-0.09 -0.11* 

(0.06) (0.07) 

Hybrid 0.10** 0.10* 

(0.05) (0.05) 

0.18*** 0.18*** 

(0.06) (0.07) 

0.10 0.07 

(0.08) (0.10) 

Plug-In Hybrid 

Electric 

0.09 0.09 

(0.08) (0.09) 

-0.05 -0.03 

(0.04) (0.05) 

0.05 -0.03 

(0.07) (0.12) 

Full Electric 0.02 -0.00 

(0.06) (0.06) 

-0.02 -0.01 

(0.03) (0.05) 

0.00 0.00 

(.) (.) 

Stop-Start -0.02 -0.02 

(0.03) (0.03) 

0.01 0.02 

(0.03) (0.04) 

0.02 0.01 

(0.03) (0.04) 

High Speed 

Automatic 

-0.00 0.01 

(0.02) (0.02) 

-0.01 0.02 

(0.03) (0.02) 

0.02 0.02 

(0.02) (0.02) 

CVT 0.07 0.06 

(0.04) (0.04) 

-0.09* -0.04 

(0.05) (0.05) 

-0.07 -0.05 

(0.05) (0.06) 

DCT 0.00 0.00 

(0.03) (0.03) 

-0.01 0.00 

(0.03) (0.03) 

-0.03 -0.02 

(0.04) (0.04) 

Elec Assist / Low 

Drag Brakes 

-0.01 -0.03 

(0.02) (0.05) 

Lighting-LED -0.10*** -0.11*** 

(0.03) (0.04) 

Mass Reduction 0.03 0.02 

(0.03) (0.03) 

Passive 

Aerodynamics 

0.04 0.03 

(0.04) (0.04) 

Observations 

Adj-R2 

1003 

0.04 

718 

0.05 

660 

0.04 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Brake Feel” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

39
 
 

 

Draft – Subject to Revision 

Table A9: "Stopping ability" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.01 -0.01 

(0.01) (0.02) 

Active Grille 

Shutters 

-0.07 -0.05 

(0.04) (0.04) 

Active Ride Height 0.01 0.01 

(0.02) (0.02) 

Low Resistance 

Tires 

0.03 0.01 

(0.07) (0.07) 

0.08 0.07 

(0.06) (0.06) 

0.09 0.05 

(0.08) (0.08) 

Electronic Power 

Steering 

0.02 0.02 

(0.02) (0.02) 

0.00 0.01 

(0.02) (0.02) 

-0.02 -0.01 

(0.02) (0.03) 

Turbocharged -0.01 -0.00 

(0.01) (0.02) 

-0.00 0.00 

(0.02) (0.03) 

0.01 0.00 

(0.04) (0.04) 

GDI -0.01 -0.01 

(0.02) (0.02) 

-0.01 -0.01 

(0.02) (0.03) 

-0.02 -0.03 

(0.03) (0.04) 

Cylinder 

Deactivation 

0.04 0.05 

(0.05) (0.05) 

0.05** 0.07*** 

(0.02) (0.03) 

0.08*** 0.09*** 

(0.03) (0.03) 

Diesel 0.01 0.02 

(0.03) (0.03) 

0.00 0.03 

(0.03) (0.04) 

-0.00 0.02 

(0.05) (0.06) 

Hybrid 0.02 0.00 

(0.03) (0.03) 

0.02 0.05 

(0.04) (0.04) 

-0.00 0.03 

(0.02) (0.04) 

Plug-In Hybrid 

Electric 

0.02 0.01 

(0.05) (0.05) 

-0.02 -0.02 

(0.06) (0.05) 

-0.05 -0.04 

(0.05) (0.06) 

Full Electric 0.05 0.03 

(0.05) (0.06) 

-0.01 -0.03 

(0.02) (0.04) 

0.00 0.00 

(.) (.) 

Stop-Start -0.00 -0.00 

(0.02) (0.02) 

-0.03 -0.02 

(0.02) (0.02) 

-0.04 -0.04 

(0.03) (0.03) 

High Speed 

Automatic 

-0.03** -0.02 

(0.01) (0.01) 

-0.02 0.01 

(0.02) (0.02) 

-0.02 0.01 

(0.02) (0.02) 

CVT 0.06* 0.06* 

(0.03) (0.03) 

0.07 0.08** 

(0.05) (0.04) 

0.08* 0.09** 

(0.04) (0.04) 

DCT 0.04 0.03 

(0.03) (0.03) 

0.05 0.07* 

(0.03) (0.04) 

0.07* 0.07* 

(0.04) (0.04) 

Elec Assist / Low 

Drag Brakes 

0.10 0.08 

(0.16) (0.16) 

Lighting-LED -0.07** -0.08** 

(0.03) (0.03) 

Mass Reduction -0.03 -0.03 

(0.02) (0.02) 

Passive 

Aerodynamics 

-0.01 0.00 

(0.03) (0.03) 

Observations 

Adj-R2 

1003 

0.02 

718 

0.03 

660 

0.04 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Stopping Ability” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

40
 
 

 

Draft – Subject to Revision 

Table A10: "General braking" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam 0.01 0.02 

(0.01) (0.02) 

Active Grille 

Shutters 

-0.01 -0.01 

(0.04) (0.04) 

Active Ride Height 0.01 0.03 

(0.02) (0.02) 

Low Resistance 

Tires 

0.00 -0.01 

(0.01) (0.02) 

0.03 -0.01 

(0.04) (0.05) 

0.06 0.04 

(0.07) (0.07) 

Electronic Power 

Steering 

-0.01 -0.01 

(0.01) (0.01) 

0.03* 0.03 

(0.02) (0.02) 

0.01 0.02 

(0.02) (0.02) 

Turbocharged -0.01 -0.00 

(0.01) (0.01) 

-0.01 0.01 

(0.01) (0.02) 

0.02 0.05 

(0.03) (0.04) 

GDI -0.02** -0.01* 

(0.01) (0.01) 

-0.03 -0.03 

(0.02) (0.03) 

-0.02 -0.01 

(0.03) (0.03) 

Cylinder 

Deactivation 

-0.02 -0.02 

(0.02) (0.02) 

-0.01 0.01 

(0.02) (0.02) 

-0.02 -0.01 

(0.03) (0.03) 

Diesel -0.01 -0.02 

(0.01) (0.01) 

-0.00 0.00 

(0.01) (0.02) 

-0.00 0.03 

(0.02) (0.03) 

Hybrid 0.05 0.05 

(0.03) (0.04) 

0.05 0.04 

(0.04) (0.05) 

0.12 0.12 

(0.08) (0.09) 

Plug-In Hybrid 

Electric 

0.05 0.05 

(0.06) (0.07) 

-0.01 -0.01 

(0.01) (0.03) 

0.00 0.07 

(0.07) (0.09) 

Full Electric -0.00 -0.02 

(0.01) (0.03) 

0.14 0.13 

(0.13) (0.14) 

0.00 0.00 

(.) (.) 

Stop-Start -0.02 -0.02 

(0.02) (0.02) 

-0.01 0.00 

(0.02) (0.02) 

-0.02 -0.01 

(0.02) (0.02) 

High Speed 

Automatic 

-0.02* -0.02* 

(0.01) (0.01) 

-0.03 -0.02 

(0.02) (0.02) 

-0.02 -0.01 

(0.02) (0.03) 

CVT 0.00 -0.00 

(0.02) (0.02) 

-0.01 -0.00 

(0.04) (0.03) 

-0.01 0.01 

(0.03) (0.03) 

DCT -0.04 -0.05 

(0.03) (0.03) 

-0.01 0.00 

(0.02) (0.03) 

0.01 0.01 

(0.03) (0.03) 

Elec Assist / Low 

Drag Brakes 

-0.00 0.00 

(0.02) (0.02) 

Lighting-LED -0.02 -0.01 

(0.02) (0.02) 

Mass Reduction -0.00 -0.01 

(0.02) (0.02) 

Passive 

Aerodynamics 

0.06 0.07 

(0.04) (0.05) 

Observations 

Adj-R2 

1003 

0.02 

718 

0.01 

660 

0.01 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “General Braking” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

41
 
 

 

Draft – Subject to Revision 

Table A11: "Tire road noise" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam 0.05 0.03 

(0.04) (0.05) 

Active Grille 

Shutters 

0.01 0.04 

(0.02) (0.03) 

Active Ride Height 0.02 0.01 

(0.03) (0.03) 

Low Resistance 

Tires 

0.01 0.03 

(0.08) (0.10) 

-0.02 0.02 

(0.04) (0.05) 

-0.01 0.04 

(0.05) (0.06) 

Electronic Power 

Steering 

0.04 0.04 

(0.02) (0.03) 

-0.03 0.01 

(0.03) (0.03) 

-0.05 -0.03 

(0.03) (0.03) 

Turbocharged 0.03 0.03 

(0.02) (0.02) 

0.01 0.05 

(0.03) (0.03) 

0.07 0.07 

(0.05) (0.05) 

GDI -0.01 -0.01 

(0.03) (0.03) 

-0.06* -0.10** 

(0.03) (0.04) 

-0.08* -0.08 

(0.05) (0.05) 

Cylinder 

Deactivation 

-0.02 -0.02 

(0.04) (0.04) 

0.02 0.02 

(0.04) (0.04) 

0.00 0.01 

(0.05) (0.05) 

Diesel -0.02 -0.01 

(0.03) (0.03) 

-0.03 -0.03 

(0.03) (0.04) 

-0.02 -0.06 

(0.07) (0.07) 

Hybrid -0.08*** -0.08*** 

(0.02) (0.02) 

-0.07** -0.08** 

(0.03) (0.04) 

-0.05 -0.06 

(0.04) (0.05) 

Plug-In Hybrid 

Electric 

0.03 0.05 

(0.06) (0.07) 

0.05 0.03 

(0.08) (0.10) 

0.06 0.18* 

(0.08) (0.10) 

Full Electric -0.05* -0.06 

(0.03) (0.05) 

-0.09* -0.10 

(0.05) (0.07) 

0.00 0.00 

(.) (.) 

Stop-Start -0.00 0.00 

(0.04) (0.04) 

-0.01 0.01 

(0.04) (0.04) 

0.03 0.03 

(0.04) (0.04) 

High Speed 

Automatic 

0.01 -0.00 

(0.02) (0.02) 

0.03 0.04 

(0.03) (0.03) 

0.05 0.07* 

(0.03) (0.04) 

CVT -0.03 -0.02 

(0.04) (0.04) 

-0.08* -0.08* 

(0.04) (0.05) 

-0.11** -0.09 

(0.04) (0.06) 

DCT 0.08 0.08 

(0.05) (0.05) 

0.08* 0.07 

(0.04) (0.05) 

0.10** 0.11* 

(0.05) (0.06) 

Elec Assist / Low 

Drag Brakes 

-0.02 -0.01 

(0.03) (0.04) 

Lighting-LED 0.08 0.08 

(0.10) (0.10) 

Mass Reduction 0.02 0.02 

(0.04) (0.04) 

Passive 

Aerodynamics 

0.01 -0.01 

(0.04) (0.04) 

Observations 

Adj-R2 

1003 

0.11 

718 

0.14 

660 

0.15 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Tire Road Noise” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

42
 
 

 

 

Draft – Subject to Revision 

Table A12: "Wind noise" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.04 -0.02 

(0.08) (0.07) 

Active Grille 

Shutters 

0.02** 0.03 

(0.01) (0.02) 

Active Ride Height 0.02 0.02 

(0.02) (0.03) 

Low Resistance 

Tires 

-0.02 -0.02 

(0.02) (0.03) 

0.00 -0.01 

(0.03) (0.04) 

0.02 -0.01 

(0.05) (0.05) 

Electronic Power 

Steering 

0.00 0.01 

(0.02) (0.02) 

0.02 0.02 

(0.02) (0.01) 

0.02 0.03 

(0.03) (0.02) 

Turbocharged -0.01 -0.01 

(0.01) (0.01) 

-0.02 0.00 

(0.02) (0.02) 

-0.00 -0.00 

(0.03) (0.03) 

GDI -0.00 0.01 

(0.02) (0.03) 

-0.05** -0.06** 

(0.02) (0.03) 

-0.06** -0.09** 

(0.03) (0.04) 

Cylinder 

Deactivation 

-0.05** -0.06** 

(0.02) (0.02) 

-0.00 0.01 

(0.03) (0.03) 

0.01 0.04 

(0.03) (0.04) 

Diesel 0.01 0.01 

(0.03) (0.03) 

0.00 0.02 

(0.03) (0.04) 

-0.01 0.02 

(0.05) (0.06) 

Hybrid -0.01 -0.02 

(0.01) (0.01) 

-0.00 -0.02 

(0.01) (0.03) 

-0.01 -0.05 

(0.02) (0.04) 

Plug-In Hybrid 

Electric 

0.01 0.01 

(0.01) (0.02) 

0.00 -0.05 

(0.02) (0.04) 

0.02 -0.07 

(0.06) (0.09) 

Full Electric -0.02 -0.03 

(0.02) (0.02) 

-0.06* -0.11** 

(0.04) (0.05) 

0.00 0.00 

(.) (.) 

Stop-Start -0.07*** -0.07*** 

(0.02) (0.02) 

-0.01 -0.02 

(0.01) (0.02) 

-0.03 -0.02 

(0.02) (0.02) 

High Speed 

Automatic 

-0.01 -0.01 

(0.01) (0.01) 

-0.01 -0.02 

(0.02) (0.03) 

-0.03 -0.05 

(0.02) (0.03) 

CVT 0.05* 0.06** 

(0.03) (0.03) 

0.04 0.02 

(0.02) (0.03) 

0.05* 0.03 

(0.03) (0.04) 

DCT -0.05** -0.05** 

(0.02) (0.02) 

-0.04 -0.05 

(0.03) (0.03) 

-0.03 -0.06 

(0.03) (0.04) 

Elec Assist / Low 

Drag Brakes 

-0.02 0.01 

(0.03) (0.03) 

Lighting-LED -0.10*** -0.11*** 

(0.03) (0.03) 

Mass Reduction 0.01 0.01 

(0.02) (0.02) 

Passive 

Aerodynamics 

0.00 0.01 

(0.03) (0.03) 

Observations 

Adj-R2 

1003 

0.09 

718 

0.13 

660 

0.15 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Wind Noise” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

43
 
 

 

Draft – Subject to Revision 

Table A 13: "Interior noise" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam 0.01 -0.01 

(0.01) (0.02) 

Active Grille 

Shutters 

0.00 -0.00 

(0.01) (0.01) 

Active Ride Height 0.01 0.00 

(0.02) (0.02) 

Low Resistance 

Tires 

0.00 0.01 

(0.01) (0.01) 

0.02 0.05 

(0.04) (0.05) 

0.04 0.06 

(0.06) (0.06) 

Electronic Power 

Steering 

-0.01** -0.01** 

(0.01) (0.01) 

-0.03* -0.03* 

(0.02) (0.02) 

-0.03 -0.04 

(0.03) (0.03) 

Turbocharged 0.01 0.00 

(0.01) (0.01) 

-0.00 -0.01 

(0.02) (0.02) 

-0.01 -0.02 

(0.02) (0.02) 

GDI 0.00 0.01 

(0.02) (0.02) 

0.01 0.02 

(0.01) (0.02) 

0.01 0.02 

(0.02) (0.02) 

Cylinder 

Deactivation 

-0.02* -0.03* 

(0.01) (0.02) 

0.01 0.00 

(0.02) (0.02) 

0.01 0.00 

(0.02) (0.02) 

Diesel -0.00 0.00 

(0.01) (0.01) 

-0.01 -0.01 

(0.01) (0.01) 

-0.01 -0.04 

(0.03) (0.03) 

Hybrid -0.02** -0.01 

(0.01) (0.01) 

-0.00 -0.02 

(0.01) (0.01) 

-0.01 -0.05 

(0.01) (0.03) 

Plug-In Hybrid 

Electric 

-0.00 0.00 

(0.01) (0.01) 

-0.02 -0.03 

(0.01) (0.03) 

-0.01 -0.05 

(0.04) (0.05) 

Full Electric -0.02 -0.02 

(0.02) (0.02) 

-0.04 -0.06 

(0.03) (0.06) 

0.00 0.00 

(.) (.) 

Stop-Start -0.02** -0.02** 

(0.01) (0.01) 

-0.00 -0.00 

(0.01) (0.01) 

0.01 -0.00 

(0.01) (0.01) 

High Speed 

Automatic 

0.00 -0.00 

(0.01) (0.01) 

0.00 -0.01 

(0.01) (0.01) 

-0.00 -0.01 

(0.01) (0.02) 

CVT -0.02 -0.02 

(0.03) (0.03) 

-0.03 -0.04 

(0.02) (0.03) 

-0.04 -0.06* 

(0.03) (0.03) 

DCT 0.03 0.04 

(0.03) (0.03) 

0.01 -0.00 

(0.02) (0.02) 

0.01 -0.01 

(0.02) (0.02) 

Elec Assist / Low 

Drag Brakes 

-0.01 -0.01 

(0.02) (0.02) 

Lighting-LED 0.14* 0.15* 

(0.08) (0.08) 

Mass Reduction -0.01 -0.01 

(0.01) (0.01) 

Passive 

Aerodynamics 

0.02 0.01 

(0.03) (0.03) 

Observations 

Adj-R2 

1003 

0.05 

718 

0.03 

660 

0.02 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Interior Noise” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

44
 
 

 

Draft – Subject to Revision 

Table A14: "Powertrain noise" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.02 -0.00 

(0.06) (0.06) 

Active Grille 

Shutters 

-0.34*** -0.31*** 

(0.10) (0.10) 

Active Ride Height -0.22*** -0.22*** 

(0.08) (0.08) 

Low Resistance 

Tires 

0.01 0.04 

(0.11) (0.12) 

-0.02 -0.05 

(0.08) (0.10) 

0.04 -0.01 

(0.12) (0.13) 

Electronic Power 

Steering 

0.01 0.01 

(0.03) (0.03) 

-0.02 -0.01 

(0.04) (0.04) 

-0.07* -0.04 

(0.04) (0.04) 

Turbocharged 0.00 0.02 

(0.03) (0.03) 

0.02 0.04 

(0.05) (0.04) 

-0.05 -0.02 

(0.08) (0.07) 

GDI -0.03 -0.04 

(0.04) (0.04) 

-0.02 -0.03 

(0.04) (0.05) 

-0.10* -0.09* 

(0.05) (0.05) 

Cylinder 

Deactivation 

0.04 0.05 

(0.06) (0.07) 

0.02 0.03 

(0.06) (0.06) 

0.03 0.05 

(0.06) (0.07) 

Diesel -0.04 -0.03 

(0.05) (0.05) 

-0.04 -0.03 

(0.06) (0.07) 

-0.09 -0.07 

(0.11) (0.11) 

Hybrid 0.07 0.04 

(0.06) (0.06) 

0.02 0.06 

(0.06) (0.07) 

0.00 0.02 

(0.11) (0.12) 

Plug-In Hybrid 

Electric 

0.19 0.24* 

(0.12) (0.12) 

0.19 0.21 

(0.15) (0.16) 

1.10*** 1.06*** 

(0.10) (0.14) 

Full Electric -0.05 -0.15 

(0.09) (0.09) 

-0.22*** -0.17** 

(0.06) (0.08) 

0.00 0.00 

(.) (.) 

Stop-Start -0.01 -0.01 

(0.05) (0.05) 

-0.05 -0.03 

(0.06) (0.06) 

-0.01 0.01 

(0.06) (0.06) 

High Speed 

Automatic 

-0.03 -0.01 

(0.03) (0.03) 

-0.04 -0.00 

(0.04) (0.05) 

-0.03 0.01 

(0.05) (0.05) 

CVT 0.16*** 0.16*** 

(0.06) (0.06) 

0.06 0.11 

(0.07) (0.08) 

0.05 0.07 

(0.08) (0.08) 

DCT -0.04 -0.04 

(0.05) (0.05) 

0.06 0.05 

(0.05) (0.06) 

0.07 0.08 

(0.05) (0.06) 

Elec Assist / Low 

Drag Brakes 

0.09 0.10 

(0.15) (0.15) 

Lighting-LED -0.19** -0.22*** 

(0.07) (0.08) 

Mass Reduction -0.01 0.00 

(0.04) (0.04) 

Passive 

Aerodynamics 

-0.06 -0.07 

(0.06) (0.05) 

Observations 

Adj-R2 

1003 

0.14 

718 

0.16 

660 

0.19 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Powertrain Noise” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

45
 
 

 

Draft – Subject to Revision 

Table A15: "General noise" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.09 -0.09 

(0.09) (0.09) 

Active Grille 

Shutters 

0.01 0.02 

(0.02) (0.02) 

Active Ride Height 0.01 0.02 

(0.03) (0.03) 

Low Resistance 

Tires 

0.04 0.04 

(0.09) (0.08) 

0.03 0.05 

(0.05) (0.06) 

0.04 0.05 

(0.07) (0.08) 

Electronic Power 

Steering 

-0.02 -0.02 

(0.02) (0.02) 

-0.02 -0.02 

(0.03) (0.03) 

-0.04 -0.02 

(0.04) (0.04) 

Turbocharged -0.02 -0.01 

(0.02) (0.02) 

0.01 0.03 

(0.02) (0.03) 

-0.03 -0.05 

(0.04) (0.04) 

GDI 0.00 0.02 

(0.03) (0.03) 

-0.05* -0.06** 

(0.03) (0.03) 

-0.07** -0.07** 

(0.03) (0.03) 

Cylinder 

Deactivation 

-0.04 -0.04 

(0.04) (0.04) 

-0.01 0.00 

(0.02) (0.02) 

-0.01 0.01 

(0.03) (0.03) 

Diesel 0.00 0.00 

(0.03) (0.03) 

-0.02 -0.02 

(0.04) (0.04) 

0.00 -0.04 

(0.05) (0.06) 

Hybrid 0.03 0.01 

(0.04) (0.03) 

0.01 -0.03 

(0.04) (0.05) 

-0.05* -0.10** 

(0.03) (0.05) 

Plug-In Hybrid 

Electric 

-0.02 -0.03 

(0.02) (0.03) 

-0.02 -0.07 

(0.02) (0.04) 

-0.01 -0.11 

(0.07) (0.09) 

Full Electric 0.03 0.02 

(0.06) (0.06) 

-0.05 -0.11** 

(0.03) (0.06) 

0.00 0.00 

(.) (.) 

Stop-Start 0.02 0.02 

(0.04) (0.04) 

0.00 0.01 

(0.05) (0.05) 

0.01 0.01 

(0.04) (0.05) 

High Speed 

Automatic 

-0.04*** -0.04** 

(0.02) (0.02) 

-0.02 -0.02 

(0.03) (0.03) 

-0.00 -0.01 

(0.03) (0.04) 

CVT 0.05 0.04 

(0.05) (0.05) 

-0.03 -0.05 

(0.06) (0.06) 

-0.02 -0.04 

(0.06) (0.06) 

DCT 0.01 0.01 

(0.04) (0.04) 

0.01 -0.02 

(0.04) (0.04) 

0.03 0.00 

(0.03) (0.04) 

Elec Assist / Low 

Drag Brakes 

-0.06** -0.06 

(0.02) (0.04) 

Lighting-LED -0.09 -0.09 

(0.08) (0.08) 

Mass Reduction -0.01 -0.01 

(0.02) (0.03) 

Passive 

Aerodynamics 

-0.02 -0.01 

(0.04) (0.04) 

Observations 

Adj-R2 

1003 

0.14 

718 

0.17 

660 

0.20 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “General Noise” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

46
 
 

 

Draft – Subject to Revision 

Table A16: "Chassis vibration" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.00 -0.00 

(0.01) (0.01) 

Active Grille 

Shutters 

-0.00 0.00 

(0.01) (0.01) 

Active Ride Height 0.01 -0.00 

(0.00) (0.00) 

Low Resistance 

Tires 

-0.00 -0.00 

(0.01) (0.01) 

-0.00 -0.00 

(0.00) (0.01) 

-0.01 -0.02 

(0.01) (0.02) 

Electronic Power 

Steering 

0.02 0.02* 

(0.01) (0.01) 

0.01 0.01 

(0.01) (0.01) 

0.01 0.01 

(0.01) (0.01) 

Turbocharged 0.01 0.00 

(0.01) (0.01) 

-0.00 -0.01 

(0.00) (0.00) 

-0.01 -0.01 

(0.01) (0.01) 

GDI -0.02* -0.01 

(0.01) (0.01) 

0.00 0.00 

(0.01) (0.01) 

-0.00 -0.00 

(0.01) (0.01) 

Cylinder 

Deactivation 

-0.04 -0.03 

(0.02) (0.02) 

-0.01 -0.01 

(0.01) (0.01) 

-0.00 -0.00 

(0.01) (0.01) 

Diesel 0.00 0.00 

(0.00) (0.01) 

0.00 0.01 

(0.01) (0.01) 

0.02 0.01 

(0.01) (0.01) 

Hybrid -0.01 -0.01 

(0.01) (0.01) 

-0.01 -0.00 

(0.01) (0.01) 

-0.00 0.01 

(0.01) (0.01) 

Plug-In Hybrid 

Electric 

-0.01 -0.01 

(0.01) (0.01) 

-0.00 0.00 

(0.01) (0.01) 

-0.04 -0.02 

(0.04) (0.04) 

Full Electric 0.01 0.02 

(0.01) (0.01) 

0.01 0.01 

(0.01) (0.01) 

0.00 0.00 

(.) (.) 

Stop-Start -0.00 -0.01 

(0.01) (0.01) 

-0.00 -0.00 

(0.00) (0.00) 

-0.01 -0.00 

(0.01) (0.01) 

High Speed 

Automatic 

0.00 0.00 

(0.01) (0.01) 

0.00 0.01 

(0.00) (0.01) 

0.00 0.01 

(0.00) (0.01) 

CVT 0.01 0.01 

(0.01) (0.01) 

0.01 0.01 

(0.01) (0.02) 

0.01 0.02 

(0.01) (0.02) 

DCT 0.01 0.01 

(0.01) (0.02) 

0.01 0.02 

(0.01) (0.02) 

0.02 0.02 

(0.02) (0.02) 

Elec Assist / Low 

Drag Brakes 

-0.01 -0.02 

(0.02) (0.02) 

Lighting-LED 0.01* 0.01 

(0.01) (0.01) 

Mass Reduction -0.01* -0.01* 

(0.01) (0.01) 

Passive 

Aerodynamics 

-0.01 -0.01 

(0.01) (0.01) 

Observations 

Adj-R2 

1003 

0.02 

718 

-0.01 

660 

-0.02 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Chassis Vibration” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on 

all technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

47
 
 

 

Draft – Subject to Revision 

Table A17: "Powertrain vibration" negative review linear probability model regressions on efficiency 

technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.01 -0.01 

(0.01) (0.01) 

Active Grille 

Shutters 

-0.00 0.00 

(0.01) (0.01) 

Active Ride Height -0.01 -0.02 

(0.02) (0.02) 

Low Resistance 

Tires 

-0.01 -0.01 

(0.01) (0.01) 

-0.01 -0.01 

(0.01) (0.01) 

-0.02* -0.03 

(0.01) (0.02) 

Electronic Power 

Steering 

0.00 0.00 

(0.01) (0.01) 

-0.01 -0.01 

(0.02) (0.02) 

-0.01 -0.02 

(0.02) (0.02) 

Turbocharged 0.01 0.01 

(0.01) (0.01) 

0.01 0.01 

(0.01) (0.01) 

0.01 0.00 

(0.03) (0.03) 

GDI -0.01 -0.01 

(0.01) (0.01) 

0.00 -0.00 

(0.01) (0.01) 

-0.00 -0.00 

(0.01) (0.01) 

Cylinder 

Deactivation 

0.01 0.02 

(0.02) (0.03) 

0.02 0.02 

(0.02) (0.02) 

0.02 0.02 

(0.02) (0.02) 

Diesel 0.01 0.01 

(0.02) (0.02) 

0.01 0.01 

(0.02) (0.02) 

-0.02 -0.03 

(0.03) (0.03) 

Hybrid -0.00 -0.00 

(0.00) (0.00) 

-0.00 0.00 

(0.00) (0.01) 

-0.00 0.01 

(0.01) (0.02) 

Plug-In Hybrid 

Electric 

-0.00 0.01 

(0.01) (0.01) 

-0.00 -0.00 

(0.01) (0.01) 

-0.00 -0.02 

(0.04) (0.04) 

Full Electric -0.01 -0.00 

(0.01) (0.01) 

-0.01 -0.00 

(0.01) (0.01) 

0.00 0.00 

(.) (.) 

Stop-Start 0.01 0.01 

(0.02) (0.02) 

-0.00 -0.01 

(0.02) (0.02) 

-0.01 -0.01 

(0.03) (0.03) 

High Speed 

Automatic 

0.00 0.00 

(0.01) (0.01) 

0.01 0.00 

(0.01) (0.01) 

0.01 0.02 

(0.01) (0.01) 

CVT 0.01 0.01 

(0.01) (0.01) 

0.01 0.01 

(0.02) (0.02) 

-0.00 0.01 

(0.02) (0.02) 

DCT 0.01 0.01 

(0.02) (0.02) 

-0.02* -0.02 

(0.01) (0.01) 

-0.01 -0.01 

(0.01) (0.01) 

Elec Assist / Low 

Drag Brakes 

-0.02 -0.02 

(0.02) (0.03) 

Lighting-LED -0.01 -0.01 

(0.01) (0.01) 

Mass Reduction 0.00 0.01 

(0.01) (0.02) 

Passive 

Aerodynamics 

-0.02* -0.02* 

(0.01) (0.01) 

Observations 

Adj-R2 

1003 

0.01 

718 

0.02 

660 

0.02 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Powertrain Vibration” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions 

on all technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported 

in parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

48
 
 

 

Draft – Subject to Revision 

Table A18: "General vibration" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam 0.01 -0.01 

(0.02) (0.02) 

Active Grille 

Shutters 

-0.00 -0.01 

(0.01) (0.02) 

Active Ride Height -0.01 -0.01 

(0.01) (0.01) 

Low Resistance 

Tires 

0.06 0.08 

(0.06) (0.06) 

0.01 0.00 

(0.01) (0.02) 

-0.00 -0.00 

(0.02) (0.02) 

Electronic Power 

Steering 

-0.01 -0.02 

(0.01) (0.01) 

0.01 0.01 

(0.01) (0.01) 

0.01 0.02 

(0.01) (0.01) 

Turbocharged -0.00 -0.00 

(0.01) (0.01) 

0.02 0.02 

(0.01) (0.02) 

0.02 0.02 

(0.02) (0.03) 

GDI 0.02 0.02 

(0.02) (0.02) 

0.01 0.01 

(0.01) (0.01) 

0.00 -0.00 

(0.01) (0.01) 

Cylinder 

Deactivation 

0.02 0.01 

(0.02) (0.02) 

-0.01 -0.02 

(0.01) (0.01) 

-0.01 -0.02 

(0.01) (0.02) 

Diesel -0.01* -0.01 

(0.01) (0.01) 

-0.01 -0.02 

(0.01) (0.02) 

-0.03 -0.03 

(0.03) (0.04) 

Hybrid -0.01 -0.01 

(0.01) (0.01) 

-0.01 0.00 

(0.01) (0.02) 

-0.03 -0.01 

(0.02) (0.03) 

Plug-In Hybrid 

Electric 

0.00 0.02 

(0.01) (0.01) 

0.00 0.02 

(0.01) (0.02) 

0.06 0.10* 

(0.04) (0.06) 

Full Electric -0.01 -0.03 

(0.01) (0.02) 

0.00 0.01 

(0.02) (0.02) 

0.00 0.00 

(.) (.) 

Stop-Start 0.03 0.03 

(0.03) (0.03) 

0.01 0.01 

(0.02) (0.02) 

0.01 0.02 

(0.02) (0.02) 

High Speed 

Automatic 

-0.00 0.00 

(0.01) (0.01) 

-0.00 0.00 

(0.02) (0.02) 

-0.00 0.01 

(0.02) (0.02) 

CVT 0.02 0.02 

(0.02) (0.02) 

0.03 0.04 

(0.02) (0.03) 

0.04 0.04 

(0.03) (0.03) 

DCT 0.03 0.03 

(0.03) (0.03) 

0.01 0.01 

(0.03) (0.03) 

0.02 0.04 

(0.04) (0.04) 

Elec Assist / Low 

Drag Brakes 

-0.01 -0.02 

(0.02) (0.03) 

Lighting-LED 0.01 0.01 

(0.01) (0.02) 

Mass Reduction 0.00 0.01 

(0.02) (0.02) 

Passive 

Aerodynamics 

-0.04** -0.04*** 

(0.01) (0.02) 

Observations 

Adj-R2 

1003 

0.06 

718 

0.10 

660 

0.11 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “General Vibration” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on 

all technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

49
 
 

 

 

Draft – Subject to Revision 

Table A19: "Ride comfort" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam -0.02 -0.04 

(0.13) (0.14) 

Active Grille 

Shutters 

-0.03 -0.05 

(0.05) (0.06) 

Active Ride Height -0.05 0.03 

(0.05) (0.07) 

Low Resistance 

Tires 

0.11 0.08 

(0.11) (0.10) 

-0.18*** -0.15** 

(0.05) (0.06) 

-0.13* -0.14* 

(0.07) (0.08) 

Electronic Power 

Steering 

-0.00 -0.02 

(0.03) (0.03) 

-0.09** -0.05 

(0.04) (0.05) 

-0.07 -0.05 

(0.05) (0.05) 

Turbocharged -0.04 -0.03 

(0.03) (0.03) 

-0.08** -0.08* 

(0.04) (0.05) 

0.02 0.00 

(0.07) (0.08) 

GDI 0.07 0.05 

(0.05) (0.05) 

-0.06 -0.04 

(0.04) (0.05) 

-0.03 -0.02 

(0.05) (0.06) 

Cylinder 

Deactivation 

0.06 0.04 

(0.08) (0.08) 

0.08 0.07 

(0.06) (0.07) 

0.05 0.08 

(0.08) (0.08) 

Diesel -0.14*** -0.12** 

(0.05) (0.05) 

-0.19*** -0.10* 

(0.05) (0.06) 

0.07 0.05 

(0.10) (0.10) 

Hybrid -0.01 -0.02 

(0.05) (0.05) 

-0.01 -0.01 

(0.05) (0.07) 

0.00 0.05 

(0.07) (0.09) 

Plug-In Hybrid 

Electric 

-0.09** -0.12** 

(0.04) (0.05) 

-0.08 -0.08 

(0.10) (0.10) 

0.00 0.12 

(0.11) (0.16) 

Full Electric 0.08 0.10 

(0.09) (0.08) 

-0.16*** -0.12 

(0.06) (0.07) 

0.00 0.00 

(.) (.) 

Stop-Start 0.00 0.02 

(0.07) (0.07) 

-0.07 -0.02 

(0.07) (0.07) 

0.05 0.05 

(0.07) (0.07) 

High Speed 

Automatic 

0.01 0.02 

(0.03) (0.03) 

-0.02 0.00 

(0.04) (0.04) 

-0.01 0.01 

(0.04) (0.05) 

CVT -0.02 -0.01 

(0.05) (0.05) 

-0.08 -0.04 

(0.05) (0.06) 

-0.10* -0.05 

(0.06) (0.07) 

DCT 0.06 0.06 

(0.06) (0.06) 

0.20*** 0.15** 

(0.06) (0.07) 

0.18** 0.17** 

(0.07) (0.08) 

Elec Assist / Low 

Drag Brakes 

-0.06 -0.09* 

(0.05) (0.05) 

Lighting-LED -0.10 -0.11 

(0.10) (0.10) 

Mass Reduction 0.07 0.07 

(0.05) (0.05) 

Passive 

Aerodynamics 

-0.02 -0.03 

(0.06) (0.07) 

Observations 

Adj-R2 

1003 

0.12 

718 

0.16 

660 

0.16 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Ride Comfort” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

50
 
 

 

Draft – Subject to Revision 

Table A20: "Fuel economy" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam 0.05 0.06 

(0.05) (0.06) 

Active Grille 

Shutters 

-0.09 -0.05 

(0.06) (0.07) 

Active Ride Height -0.25** -0.18* 

(0.11) (0.09) 

Low Resistance 

Tires 

-0.17*** -0.17*** 

(0.04) (0.05) 

-0.18** -0.16* 

(0.07) (0.08) 

-0.15 -0.24** 

(0.11) (0.12) 

Electronic Power 

Steering 

0.01 0.02 

(0.03) (0.03) 

-0.12** -0.11** 

(0.05) (0.05) 

-0.10* -0.13** 

(0.06) (0.06) 

Turbocharged 0.02 0.04 

(0.03) (0.03) 

-0.00 0.03 

(0.04) (0.05) 

0.01 -0.06 

(0.08) (0.09) 

GDI -0.09*** -0.05 

(0.03) (0.03) 

-0.09* -0.10* 

(0.05) (0.06) 

-0.11* -0.05 

(0.06) (0.07) 

Cylinder 

Deactivation 

-0.17*** -0.14** 

(0.06) (0.06) 

-0.09 -0.10 

(0.06) (0.06) 

-0.15** -0.15** 

(0.07) (0.08) 

Diesel -0.13*** -0.15*** 

(0.04) (0.05) 

-0.10* -0.09 

(0.06) (0.06) 

-0.21** -0.33*** 

(0.09) (0.11) 

Hybrid -0.02 -0.02 

(0.05) (0.05) 

0.01 -0.02 

(0.07) (0.08) 

0.20 0.17 

(0.12) (0.13) 

Plug-In Hybrid 

Electric 

-0.06 -0.06 

(0.07) (0.06) 

-0.09 -0.12 

(0.09) (0.11) 

-0.25* -0.53*** 

(0.14) (0.20) 

Full Electric -0.05 0.01 

(0.07) (0.07) 

-0.16*** -0.17** 

(0.06) (0.08) 

0.00 0.00 

(.) (.) 

Stop-Start -0.02 -0.01 

(0.06) (0.06) 

-0.12* -0.12* 

(0.06) (0.07) 

-0.11 -0.13* 

(0.07) (0.07) 

High Speed 

Automatic 

-0.04 -0.05* 

(0.02) (0.03) 

0.00 -0.00 

(0.04) (0.04) 

-0.04 -0.01 

(0.04) (0.05) 

CVT -0.04 -0.04 

(0.06) (0.06) 

-0.04 -0.01 

(0.07) (0.08) 

-0.04 0.01 

(0.08) (0.09) 

DCT -0.03 -0.06 

(0.03) (0.04) 

0.01 -0.08 

(0.05) (0.06) 

-0.01 -0.03 

(0.06) (0.07) 

Elec Assist / Low 

Drag Brakes 

-0.13** -0.11* 

(0.07) (0.06) 

Lighting-LED -0.15* -0.14 

(0.09) (0.10) 

Mass Reduction -0.07** -0.07** 

(0.03) (0.03) 

Passive 

Aerodynamics 

0.01 0.06 

(0.05) (0.05) 

Observations 

Adj-R2 

1003 

0.13 

718 

0.10 

660 

0.14 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Fuel Economy” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

51
 
 

 

Draft – Subject to Revision 

Table A21: "Range" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam 0.01 0.00 

(0.01) (0.01) 

Active Grille 

Shutters 

0.00 0.00 

(0.00) (0.00) 

Active Ride Height 0.00 0.00 

(0.01) (0.01) 

Low Resistance 

Tires 

0.05 0.02 

(0.07) (0.07) 

0.01 -0.03 

(0.03) (0.03) 

-0.01 0.00 

(0.01) (0.01) 

Electronic Power 

Steering 

0.00 0.00 

(0.01) (0.01) 

0.00 0.00 

(0.00) (0.01) 

0.00 -0.00 

(0.00) (0.00) 

Turbocharged -0.01** -0.00 

(0.01) (0.00) 

-0.01 0.01 

(0.01) (0.01) 

0.02 0.02 

(0.02) (0.02) 

GDI 0.00 0.00 

(0.00) (0.00) 

-0.01 0.01 

(0.01) (0.01) 

0.01 0.02 

(0.01) (0.01) 

Cylinder 

Deactivation 

0.01* 0.01 

(0.01) (0.01) 

0.00 0.00 

(0.01) (0.01) 

0.00 -0.01 

(0.00) (0.01) 

Diesel -0.01 -0.01 

(0.01) (0.01) 

-0.00 -0.01 

(0.01) (0.01) 

-0.01 -0.01 

(0.02) (0.02) 

Hybrid -0.02* -0.01 

(0.01) (0.01) 

-0.02 -0.00 

(0.01) (0.01) 

-0.00 0.00 

(0.00) (0.01) 

Plug-In Hybrid 

Electric 

0.28*** 0.27** 

(0.11) (0.11) 

0.26** 0.28** 

(0.12) (0.12) 

-0.02 0.02 

(0.02) (0.03) 

Full Electric 0.10 0.02 

(0.08) (0.08) 

-0.02 0.04 

(0.01) (0.03) 

0.00 0.00 

(.) (.) 

Stop-Start 0.01 0.02 

(0.02) (0.02) 

0.00 0.01 

(0.00) (0.01) 

-0.00 -0.00 

(0.00) (0.01) 

High Speed 

Automatic 

-0.01 -0.00 

(0.00) (0.00) 

-0.01 0.01 

(0.01) (0.01) 

0.01 0.01 

(0.01) (0.01) 

CVT -0.02* -0.02** 

(0.01) (0.01) 

-0.02* -0.01 

(0.01) (0.01) 

-0.01 -0.01 

(0.01) (0.01) 

DCT -0.00 0.00 

(0.00) (0.00) 

-0.00 0.01 

(0.00) (0.01) 

0.00 0.01 

(0.01) (0.01) 

Elec Assist / Low 

Drag Brakes 

-0.00 -0.00 

(0.01) (0.02) 

Lighting-LED -0.01 -0.00 

(0.01) (0.01) 

Mass Reduction -0.01* -0.01 

(0.00) (0.01) 

Passive 

Aerodynamics 

0.02 0.00 

(0.03) (0.02) 

Observations 

Adj-R2 

1003 

0.17 

718 

0.14 

660 

0.01 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Range” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

52
 
 

 

Draft – Subject to Revision 

Table A22: "Charging" negative review linear probability model regressions on efficiency technology 

Any coded mention of 

tech in review 

Tech Data Tech Data plus vehicle 

attributes 

Single All tech Single All tech Single All tech 

Active Air Dam 0.00 0.00 

(0.00) (0.00) 

Active Grille 

Shutters 

0.00 0.00 

(0.00) (0.00) 

Active Ride Height 0.01 0.00 

(0.00) (0.01) 

Low Resistance 

Tires 

0.00 -0.01 

(0.00) (0.02) 

0.08* 0.05* 

(0.04) (0.03) 

Electronic Power 

Steering 

-0.00 -0.00 

(0.00) (0.00) 

0.01 0.01 

(0.00) (0.00) 

Turbocharged -0.00 -0.00 

(0.00) (0.00) 

-0.01 0.00 

(0.01) (0.00) 

GDI -0.00 0.00 

(0.00) (0.00) 

-0.02* -0.00 

(0.01) (0.00) 

Cylinder 

Deactivation 

-0.00 -0.00 

(0.00) (0.00) 

-0.01 -0.00 

(0.01) (0.00) 

Diesel 0.01 0.01 

(0.00) (0.00) 

0.01 0.00 

(0.01) (0.01) 

Hybrid 0.00 0.00 

(0.00) (0.00) 

0.00 0.00 

(0.00) (0.00) 

Plug-In Hybrid 

Electric 

0.09 0.10 

(0.06) (0.08) 

0.07 0.06 

(0.05) (0.05) 

Full Electric 0.03 0.00 

(0.05) (0.07) 

0.10 0.08 

(0.12) (0.11) 

Stop-Start -0.00 0.00 

(0.00) (0.00) 

0.00 0.01 

(0.00) (0.00) 

High Speed 

Automatic 

-0.00 -0.00 

(0.00) (0.00) 

-0.01* 0.00 

(0.01) (0.00) 

CVT 0.00 0.00 

(0.00) (0.00) 

0.00 -0.00 

(0.00) (0.00) 

DCT -0.00 -0.00 

(0.00) (0.00) 

-0.01 0.00 

(0.01) (0.00) 

Elec Assist / Low 

Drag Brakes 

-0.01 -0.00 

(0.01) (0.01) 

Lighting-LED 0.00 0.01 

(0.00) (0.00) 

Mass Reduction 0.01 0.02 

(0.02) (0.02) 

Passive 

Aerodynamics 

0.00 -0.01 

(0.00) (0.01) 

Observations 

Adj-R2 

1003 

0.07 

718 

0.10 

Results in the “Single” columns represent coefficient estimates for individual linear probability model (OLS) regressions of a negative 

review of “Charging” on the single technology given by the row plus fixed effects. The “All tech” columns represent single regressions on all 

technology variables. All regressions include make, class, and review website fixed effects. Eicker–Huber–White standard errors are reported in 

parentheses. Asterisks designate statistical significance at the 10% (*), 5% (**), and 1% (***) levels. 

53