BLS WORKING PAPERS 

 

U.S. Department of Labor 

U.S. Bureau of Labor Statistics 

Office of Productivity and Technology 

R&D and Productivity Growth: A Review of the Literature 

Leo Sveikauskas, U.S. Bureau of Labor Statistics 

Working Paper 408

September 2007

All views expressed in this paper are those of the author and do not necessarily reflect the views or policies of the 

U.S. Bureau of Labor Statistics. 
 R&D and Productivity Growth: A Review of the Literature1

 Leo Sveikauskas 

 Division of Productivity Research and Program Development 

 Bureau of Labor Statistics, Washington, D.C. 20212 

 Bureau of Labor Statistics Working Paper 408 

 Abstract 

 This paper reviews the literature on R&D to provide guidelines for recent efforts to 

include R&D in the national income accounts. The main conclusions are: 

 1. Measures of R&D as an asset held by a particular owner must be complemented 

by estimates of the spillover effect of R&D in order to obtain a reliable measure of the 

overall effect of R&D on productivity growth. 

 2. If research financed by the government and research financed by business are 

both counted as investment, some double counting occurs and growth accounting analysis 

overstates the role of research relative to other factors. 

 3. The overall rate of return to R&D is very large, perhaps 25 percent as a private 

return and a total of 65 percent for social returns. However, these returns apply only to 

privately financed R&D in industry. Returns to many forms of publicly financed R&D 

are near zero. 

 4. Firm R&D should be allocated to the different industries in which a firm 

produces, rather than all credited to the firm’s main industry. An allocation procedure is 

proposed. 

 5. Much further work needs to be carried out to understand how R&D conducted in 

the richest countries is transmitted to developing countries. Detailed microeconomic data 

on firms or establishments in developing nations will be necessary to understand the 

channels of technology transfer more fully. 

Journal of Economic Literature categories: O30, O40. 

Keywords: R&D stocks, R&D spillovers, R&D and productivity growth 

 

1

 This paper reviews several portions of the scholarly literature on research and development which are 

relevant to current efforts to establish R&D satellite accounts. I appreciate comments from Michael 

Harper, Peter Meyer, Carol Robbins, and Larry Rosenblum, and remarks from seminar participants at the 

Bureau of Economic Analysis and the Bureau of Labor Statistics. However, the views expressed in this 

paper are solely those of the author, and do not reflect the views or policies of the U.S. Bureau of Labor 

Statistics or the Bureau of Economic Analysis. 
2

 R&D and Productivity Growth: A Review of the Literature 

 Leo Sveikauskas2

 Bureau of Labor Statistics 

 

 Recent years have seen substantial progress towards including research and 

development (R&D) as a capital investment within the national income accounts 

(Canberra Group II (2003)). Economists at the United States Bureau of Economic 

Analysis, or BEA, (Carson, Grimm and Moylan (1994), Fraumeni and Okubo (2005); 

Okubo et al (2006b)) have prepared initial versions of a potential R&D satellite account. 

The U.S. National Science Foundation has agreed to support BEA’s further work on 

R&D accounts, and the BEA is committed to publish R&D accounts for the United 

States. Economists in Australia (Australian Bureau of Statistics (2004)) and in the 

Netherlands (de Haan (2004)) have also reported initial R&D stocks for their countries. 

 One main motive for adding R&D is to broaden the accounts to include a 

further important source of economic growth. Present international discussion has 

largely concentrated on treating R&D as an asset for private firms, the government, 

universities, and other nonprofit organizations. However, most gains from R&D 

typically do not accrue to the original investors. Benefits instead spill over to a wide 

variety of other economic agents. Consequently, it is necessary to establish links 

between the role of R&D as an asset and the total effect of R&D on economic growth, 

which reflects both asset returns and spillovers. 

 

 

2

 The views expressed here are those of the author, and do not represent the Bureau of Labor Statistics. 
3

 Many central characteristics of R&D stocks, such as the rate of depreciation, the lag 

until R&D becomes operative, and the rate of return, differ widely between the asset and 

spillover effects. In a sense, analysts have to prepare two different sets of calculations to 

describe the asset and spillover effects of R&D. From this perspective, the stocks of 

R&D assets the U.S. Bureau of Economic Analysis is currently preparing neatly 

complement the spillover R&D stocks which the U.S. Bureau of Labor Statistics has 

published for many years.3 Other countries currently measuring R&D assets will 

similarly have to expand their analyses to include spillovers in order to describe the full 

impact of R&D on productivity growth. 

 This paper examines the relationship between R&D as an asset and R&D as an 

ingredient in growth. Section I considers recent measures of asset and spillover R&D 

stocks in the United States, and also examines which portions of R&D should be included 

in national R&D stocks. Section II reviews the economics literature on the private and 

social (private plus spillover) impact of R&D. Section III considers some difficulties 

associated with measuring R&D accurately in each industry. Section IV examines the 

international transmission of R&D, a major source of spillovers for most of the countries 

in the world. Section V concludes.4

 

I. Introduction: Understanding Asset and Spillover Returns to R&D; What Portions of 

R&D Should be Included in National R&D Stocks?

 

3

 Okubo et al (2006b) describe BEA work on R&D as an asset, and U.S. Bureau of Labor Statistics (1989) 

presents the BLS work on R&D spillovers. 

4

 An earlier version of the present paper was prepared as a background paper for the Canberra II 

discussion of research and development. 
4

 Most Canberra II group discussion of R&D concentrated on similarities between 

R&D and other assets already recognized as capital.5

 For example, firms commit 

resources to R&D in the hope that this investment will create an asset which eventually 

lead to greater profits, much as in the case of plant or equipment. 

 The comparison is valid, and supports the proposal that R&D expenditures should 

similarly be treated as capital investment. However, R&D differs from other forms of 

capital investment in several respects. A central characteristic is that payoffs from R&D 

are not limited to the original investors, but also accrue to competitors, other firms, 

suppliers, and customers.6 Consequently, it is too narrow to view R&D as essentially an 

asset held by a particular owner. A broader perspective on R&D has to include 

knowledge spillovers, which have often been a central theme in discussions of 

productivity growth.7 

 To illustrate the importance of the diffusion of knowledge from firms undertaking 

research to the broader community, consider technical change in pharmaceuticals. 

Statins are a new class of anti-cholesterol drugs which have contributed greatly to the 

decline of heart disease. A major pharmaceutical firm introduced the first commercial 

 

5

 The March 2004 meeting of the Canberra II group, held in Washington, discussed R&D as an asset, and 

concentrated on similarities between R&D and other assets. 

6

 Romer (1990, pp. 73-76) discusses nonrival goods, for which the use by one firm or person does not 

limit its use by another. Romer also considers excludability, and points out that the results from research 

can only partially be excluded from use by others. 

7

 Section II reviews the literature on the effect of R&D on productivity growth. 

 In addition to the nonrival characteristic of R&D knowledge, it is typically difficult to determine the 

value of output from research because research results are typically not sold on the open market. 

Economists have measured research outcomes from statistical relationships between R&D and several 

indicators of technological success. Most studies determine the return to research from its relationship with 

productivity growth. Other work evaluates the effectiveness of research from its connection with profits or 

stock market value. 
5

statin product in 1987, and conducted pioneering research demonstrating that statins were 

safe, lowered cholesterol, and successfully reduced the death rate from heart disease. 

Since 1987, several firms have introduced new and improved statins. A different firm 

now produces a new and greatly improved statin, which lowers cholesterol more 

effectively, and has therefore become the market leader. 

 

 Although the second firm now dominates the market for statins, it is not the case that 

the second firm’s private investment in R&D is now the only relevant R&D. From the 

point of view of private returns, much of the early research which the initial firm carried 

out is indeed no longer profitable.8 However, in a broader sense all the initial research 

which demonstrated that statins were safe, highly effective, and reduced the incidence of 

heart disease still provides the core knowledge of the present day industry. The first 

firm’s initial investment in R&D is still relevant to the industry and still provides 

important social returns, even though most of the private returns now go to the second 

firm. 

 To take another example, two leading firms have competed in producing 

microprocessors for many years. When the technology leader introduces a new chip, the 

second firm soon matches, and prices fall rapidly. As a result, microprocessor prices 

have declined sharply. Most of the benefits of innovation have been captured by 

consumers through lower prices. The profit of the innovators, obtained through returns to 

the R&D they conduct, is only a small part of the picture. 

 

8

 In fact, the initial drug, introduced in 1987, is no longer under patent. 
6

 These examples illustrate how the knowledge and benefits obtained from R&D 

typically leak out from the original performers of R&D to competitors, to other firms, to 

consumers, and, eventually, to other countries. Many forms of knowledge are useful to 

other firms (and so have a social return) even when they no longer pay off to the firm 

initiating the research (no longer have a private return). Similarly, consumers obtain 

better or cheaper products (benefit from social returns) even if the private return to firms 

turns out to be low.9

 As knowledge gradually leaks out, private benefits decline and spillover effects 

increase. Consequently, private and spillover returns follow different time paths. Quite 

reasonably, spillover effects are considerably more long lived than private effects. 

Okubo et al. (2006b) calculate R&D asset stocks assuming a 15 percent (or greater) 

annual depreciation rate. In contrast, the Bureau of Labor Statistics (1989), measuring 

the longer lasting spillover effects, assumes 10 percent depreciation for applied research 

and development and zero depreciation for basic research, which implies an overall 

depreciation rate of less than 9 percent.10

 Such substantial differences in depreciation have an important impact on the implied 

size of R&D stocks and the time pattern of anticipated benefits. For example, in 2000 the 

BLS spillover R&D stock is 44 percent greater than it would have been if calculated at 15 

percent depreciation. A 15 percent depreciation rate implies that a quarter of an 

 

9

 Measured benefits are limited to those which have a market evaluation. Some benefits, such as clean 

air or some types of medical advances, are not evaluated through market prices, and are typically not 

included in economic statistics. 

10 Since the BLS assumes zero depreciation of basic research, the basic research proportion of the overall 

BLS stocks is greater than data on annual R&D investments would suggest. 
7

investment has depreciated after two years, half by five years, and three-quarters by 9 

years. In contrast, 9 percent depreciation indicates a quarter of investment has 

depreciated by 4 years, half by 8 years, and three-quarters by 15 years. 

 The influence of depreciation is accentuated by differences in the lags with which 

R&D investment enters the R&D stock. BEA R&D investments enter the asset stock 

immediately, whereas BLS investments enter the spillover stock with a lag of two years 

for applied research, and five years for basic research.11 The longer lags further imply 

that spillovers occur later than asset returns. 

 There are also major differences in the returns to asset and spillover R&D. 

Somewhat surprisingly, it is quite difficult to determine exactly how much of R&D 

returns accrue through private returns and how much through spillovers. Most of the 

economics literature typically reports the amount by which the average social return to 

R&D exceeds the private return.12 Remarkably few studies (Schankerman (1981); Cuneo 

and Mairesse (1984)) actually examine the actual return to private firms, which is most 

relevant in considering R&D as an asset. 

 

11 In the BEA stocks, if investment occurs in 1990, half enters the R&D stock at the start of 1990 and 

half at the start of 1991. In the BLS calculations, 1990 investment in applied research enters the research 

stock at the start of 1992. 

12 Studies typically include the capital, labor, and other factors used in research within the inputs used to 

measure productivity growth. Therefore, the private value of research is removed from such productivity 

measures. Consequently, when R&D is used to explain productivity growth, the estimated return is the 

amount by which the return to R&D exceeds the private value of these resources. Griliches and 

Lichtenberg (1984b, page 475) and U.S. Bureau of Labor Statistics (1989, page 36) provide a more formal 

statement of this argument. 

 In other relevant literature, Nordhaus (2004) emphasizes that only a very small portion of the returns to 

R&D accrues as abnormally high returns to the innovator. Baumol (2000) describes how firms continually 

improve the quality of their products, through R&D, and leapfrog beyond the products produced by their 

competitors’ R&D; this churning process reduces the value of their competitors’ private R&D. 
8

 Nevertheless, the existing literature generally finds that spillovers are greater than 

private returns. Griliches (2000, page page 70) concludes that the excess return to 

firms13 is 10 percent, whereas the social return, which includes private returns, is 25 

percent. Section II of the present paper reviews the evidence and suggests the private 

return to R&D is 25 percent, while the social return is 65 percent. Okubo et al. (2006a, 

page 27) examine many different studies, and conclude that the private return is 26 

percent and the social return 66 percent. Each of these three judgements indicates 

spillovers contribute approximately three-fifths of the total return to R&D. 

 Of course, the conclusion that spillover effects are primary is necessarily tentative 

because the available evidence is incomplete. Clearly, most studies do not include the 

private value of resources used in research, and thereby understate the contribution of 

R&D.14 Studies of specific innovations offer an alternative method of measuring actual 

returns to private firms; subsection II.5 below examines evidence from the innovation 

studies and reaches roughly similar conclusions concerning the relative importance of 

private and spillover effects. In addition, most studies omit the international effects of 

R&D (Coe and Helpman (1995)) and thereby miss an important element of spillovers. 

 Another central question in the capitalization of R&D is which portions of R&D 

should be included as investment. The current consensus is that all private, government, 

 

13 Footnote 10 explains why the R&D literature typically reports excess returns which exceed the private 

return. 

14 Since most studies report only a portion of total returns to R&D (the excess return), the implied total 

effect of R&D will clearly be greater if the value of the private inputs used in R&D is also included. 

 In this context, a BEA analysis of industry data (Schultz (2006)) has the great virtue that it isolates the 

capital, labor, and materials used in R&D and removes these inputs from the factors used in production. If 

similar adjustments could be made within firm data, it would be possible to obtain better estimates of actual 

overall returns to each firm’s private R&D. 
9

or university R&D should be treated as investment.15 However, two issues arise here. 

First, many forms of R&D have little economic value and do not contribute to growth. 

Should they all be counted as investment? Second, if publicly financed basic research 

and subsequent private research are both treated as investment, a certain amount of 

double counting occurs. The rest of Section I examines these two topics. 

 In considering which forms of R&D should be designated as investment, the asset 

and growth views of R&D once again offer contrasting perspectives. The 1993 System 

of National Accounts defines an asset, in part, by requiring that “Economic benefits may 

be derived by their owners by holding them or using them over a period of time”. In this 

definition, the word “may” leads to an extremely broad definition of assets. Even if a 

broad category of research spending brings almost no demonstrated economic returns, 

just the possibility that a very small portion of these expenditures “may” be able to bring 

returns leads to the entire sum being classified as an asset. So it is not surprising that 

current discussion suggests that all R&D expenditures by firms, universities, and 

governments (as R&D is defined in the OECD Frascati Manual) should be treated as 

investment. 

 In contrast, from the point of view of growth, what matters is the proportion of an 

expenditure category which can be expected to provide returns and the magnitude of the 

returns. From this perspective, most discussion has emphasized privately financed 

research, which has been amply demonstrated to bring high returns. Of course, as 

Scherer (1999) pointed out, most private R&D projects do not actually earn positive 

 

15 Canberra II group (2006); Robbins (2006); Okubo et al (2006b). 
10

returns. Nevertheless, all private R&D expenditures can plausibly be treated as 

investment because these expenditures are all undertaken with the expectation of a 

commercial return and “may” obtain such returns. 

 In contrast, broad slices of university and government research are conducted with 

very little expectation or prospects of direct commercial returns.16 For example, only a 

very small part of the research conducted by universities and colleges brings commercial 

returns.17 As President Richard Levin of Yale University recently remarked “We’re not 

trying to drive university science by commercial objectives. We want to do great science. 

Some of that will have commercial potential; most of it won’t.” Also “Our technology 

transfer strategy is not to maximize revenue. Our primary goal is to get the findings of 

our laboratories out into practice.”18 

 Federally financed industrial research accounted for more than half of industrial 

research in the late 1960s, though this proportion is now less than one tenth. Evidence on 

the productivity impact of federal research in industry is mixed. The industry studies and 

the best study of firm data (Leonard (1971); Terleckyj (1974); Lichtenberg and Siegel 

 

16 Fraumeni and Okubo (2005) assume the return to public research is two-thirds of the return to private 

research, which is clearly an overstatement because they are working within the framework of the current 

national income accounts, which do not include the returns to federal investment in R&D within output. 

 More recently, government statisticians have decided to include returns to government capital as output, 

and it is clearly appropriate to include returns to government R&D stocks as well. Nevertheless, as the text 

points out, many forms of federal and university research have little economic value and do not contribute 

to growth. Even though such expenditures are classified as R&D, I would argue that, because there is no 

evidence of a positive return, such expenditures are actually a form of government consumption, often for 

quite useful purposes, but do not deserve to be treated as investment. 

17 Even universities as eminent as Michigan, Rochester, and Yale earn surprisingly small amounts from 

patent royalties. For example, over the last decade Yale earned approximately $21 million dollars a year 

from patent royalties 

18 Yale Alumni Bulletin, November 2006. 
11

(1991)) conclude federal research in industry does not improve industrial productivity.19 

In contrast, Griliches (1986) concluded federal R&D in industry had a positive effect on 

productivity, though less of an impact than privately financed research. Even beyond 

university and federally financed industrial research, Piekarz (1983) reviews evidence 

indicating that many federally funded research programs have not been very effective. 

 It is disturbing to assign investment status to broad categories of research spending, 

such as university research or federally financed R&D in industry, when the fundamental 

evidence indicates that, though returns “may” exist, actual returns are unlikely or at best 

accrue to only a small proportion of expenditures. In my judgement, large batches of 

expenditures where direct economic value is unlikely should not be treated as R&D 

investment, on the same basis as private R&D, merely on the off chance that some small 

amounts of these expenditures “may” turn out to have economic value.20 If all 

expenditures in government and university R&D are treated as investment, the true 

 

19 In the United States, federally financed research expenditures refer to research financed by the national, 

or federal, government. On the basis of the type of evidence summarized in the text, the U.S. Bureau of 

Labor Statistics (1989), in its work on productivity growth, chose to include only privately financed R&D 

conducted in industry in its measures of the relevant R&D stock. 

 Lichtenberg and Siegel (1991) is the best study of these matters within firm data because their paper 

adjusts the firm output deflators to reflect the different industries in which each firm actually produces. 

 Some papers find that federally financed research in industry has a positive effect. Bonte (2003) argues 

that federally financed research contributes to productivity growth in the United States, but his analysis is 

based on a cointegration analysis of aggregate data, and does not use the highly detailed firm data analyzed 

in Lichtenberg and Siegel (1991). 

 A potentially important recent study (Guellec and van Pottelsberge de la Potterie (2004)) argued that 

government research expenditures, given private R&D, contribute to the rate of economic growth. This 

analysis is based on aggregate data for 16 OECD countries. Such conclusions run counter to most of the 

literature, which indicates that public research affects measured growth only through its effect on private 

research (OECD (2003) in addition to the U.S. studies mentioned in the text). Without more detailed 

microeconomic evidence establishing specific channels through which public science affects productivity 

growth in these 16 countries (such as a more rapid growth of high-tech industries), the direct importance of 

government R&D in growth remains an open question. 

20 Consider a similar argument in the case of an auto dealer who is selling 100 cars, of which one or two 

“may” be used as an investment. In this context, it does not make much sense to consider all 100 cars as 

investment. Yet this is fundamentally what is being proposed in designating all university and government 

research as investment. 
12

amount of relevant R&D investment is greatly overstated.21 In my judgement, any 

procedure which counts all government or university research as equivalent, on a dollar 

for dollar basis, to private research spending provides an extremely flawed measure of 

how much economically relevant research investment actually occurs. 

 Of course, some government and university research has been greatly successful. 

Several programs, especially those in which university scientists compete for grants, such 

as the National Science Foundation, the National Institues of Health, some Department of 

Agriculture programs, and DARPA in the Department of Defense, appear to have a 

remarkable record. In addition, much federal and university research is conducted on 

health care, and Nordhaus (2003) demonstrated the importance of such work. Similarly, 

much military research substantially improved military effectiveness, as any comparison 

of the accuracy of precision guided missiles in the Gulf War of the early 1990s and in the 

Iraq war of the early 2000s clearly indicates. 

 However, these government successes have been influential primarily through their 

impact outside the public sector. For example, when physicists developed better methods 

of transmitting their papers through ARPANET, this precursor to the Internet did not 

greatly affect government output. Except for some elements of military research, each of 

 

21 As an illustration of the importance of properly defining the boundaries of research investment, in 

Lisbon the European Union adopted a goal that R&D expenditures should be three percent of GDP. Private 

R&D expenditures are falling far short of this target. The Europeans may therefore consider greater 

“investment” in university or government R&D. I would argue that the economic returns to public R&D 

are far lower than those to private R&D and that, if the Europeans follow such a strategy, they will be badly 

disappointed with the returns. Overall returns for university and government research are low primarily 

because so much research in these fields has no direct financial payoff. 
13

these major successes has probably had its greatest economic impact through the private 

sector. 

 The discussion above demonstrated much university and federal research has little 

commercial value. On the other hand, perhaps federal R&D produces more government 

output, and should therefore perhaps be assigned a rate of return, such as the Treasury bill 

rate. Such suggestions are inherently plausibile. Perhaps R&D is effective in a variety of 

circumstances, and brings government agencies useful benefits, even if these are 

currently not included in GDP. However, proposals such as these determine which R&D 

is useful by assumption rather than through evidence. If the crucial contribution of 

federal R&D to growth is through increasing government output, advocates of including 

federally financed R&D, and its returns, in the accounts need to demonstrate that federal 

R&D actually brings about increased federal output.22 Lehr and Lichtenberg (1998) 

showed it is possible to determine how new technology improves the productivity of 

government agencies. If this channel is crucial in justifying federal R&D as an 

investment, we need much better evidence on how federally financed R&D improves 

federal productivity, and on whether there are important areas in which federal R&D is 

ineffective, before federally financed R&D, and its assumed returns, can be included in 

the national accounts. 

 

22 As Section II below illustrates, the notion that private R&D contributes to growth is supported by a rich 

variety of evidence which greatly clarifies the returns to private R&D. If evidence did not consistently 

show that private R&D affects productivity and output growth, the international statistical community 

would probably not now be supporting the inclusion of private R&D as an investment. Surely, it is just as 

necessary to have sound empirical evidence demonstrating that there are returns to federal R&D before 

such expenditures are included as an asset. 
14

 It is not sufficient to finesse these points by simply assigning a lower rate of return to 

all university and federal research. The more fundamental problem is that many forms of 

research, however worthy they may be, do not deserve to be designated as investment 

because they do not contribute to the future growth of output. 

 Of course, many advances arising from university or government research eventually 

have an important indirect effect on growth. Consider, however, the usual conventions 

and methods of growth accounting. Growth accounting typically examines only the 

proximate sources of growth. For example, growth due to a higher number of educated 

workers is typically attributed to labor quality, and growth due to larger amounts of 

capital is similarly attributed to capital formation. Even if improvements in technology 

are the fundamental underlying cause, which creates the demand for a more educated 

work force or creates the new equipment which makes further capital deepening feasible, 

growth accounting still attributes these observed output gains to education and to capital 

deepening rather than to technology. In a similar way, the flow of understanding from 

federal or university research typically operates by increasing the demand for private 

R&D. If the National Institutes of Health develop new insights into the treatment of a 

particular disease, large amounts of further private R&D are usually required to convert 

these new ideas into new pharmaceuticals (Toole (2007)). Consistent with the treatment 

of other inputs in growth accounting, growth accounting should include only the private 

R&D and not the underlying public or university research which makes the private effort 

feasible. If we count both the underlying government and university research and also 
15

the proximate private R&D spending, we are in a sense double counting the investment in 

R&D in comparison with our treatment of other inputs.23

 There may be some argument for double counting in the case of military 

technology, where improved weapons directly meet an important government goal, and 

the spillovers involved in dual-use technology are peripheral. However, for other 

government research, in such areas as health, science, technology, and agriculture, the 

fundamental government goals are downstream, such as the introduction of better 

medicines or the promotion of industrial growth and technology.24 In the context of 

growth accounting, it is not appropriate to include here both the public research which 

establishes understanding and the private research which implements the new concepts. 

 In summary, if we are operating within the framework of growth accounting, only a 

relatively small proportion, perhaps a quarter or less, of the R&D conducted in 

government or in universities can be expected to have commercial returns or to bring 

firmly established imputed returns. Such a proportion is sharply lower than the twothirds suggested by Fraumeni and Okubo (2005).25

 

23 Recent empirical studies have established that certain broad economic features, such as legal 

protections for private property (Scully (1988), La Porta, Lopez-de-Silanes, Shleifer, and Vishny (1998), 

Djankov, La Porta, Lopez-de-Silanes, and Shleifer (2003)) or the presence of a large financial sector (King 

and Levine (1993)), have a positive impact on growth. In much the same way, high quality government or 

university research is likely to create a favorable framework for growth. Nevertheless, economists 

typically do not treat government expenditures on the legal or financial system as an investment. 

 In contrast, government investment in transportation infrastructure, where benefits can plausibly be 

assigned to individual firms, is often included in productivity studies. 

24 Some may argue that the government is really trying to advance science and knowledge for its own 

sake, which is a useful goal. However, if the process did not eventually lead to better treatment for diseases 

and a longer life span, funding for NIH would be much lower. 

25 As some readers have suggested, by this logic if a research team in a medical school is hired to do 

similar work in a pharmaceutical firm, such a change in the work environment will increase measured 
16

 

II. The Literature on the Rate of Return to R&D. 

 The effect of R&D on the economy depends on both what expenditures are included 

in R&D, as discussed in Section I, and what the returns to R&D are. Section II therefore 

reviews evidence on the returns to R&D. The rate of return to R&D can be examined at 

many different levels of aggregation, such as the returns to individual research projects, 

the returns to firms, returns to an industry, returns to a national economy, or even returns 

within the entire world. 

II.1 Private (Firm Level) Returns to R&D. 

 The return to research has generally been estimated (Griliches (1980)) by 

comparing productivity growth or profitability in different firms with research 

expenditures or the growth of the research stock within these firms.26 Nadiri (1993, 

Table 1a) reports the results from many studies which examined the return to R&D 

within data for individual firms. 

 Several difficulties limit the validity of estimates of the private return to R&D. 

Substantial complementary resources are often used with R&D. For example, the results 

from new research have to be put into effective operation. In many cases, producing a 

new product requires a pilot plant or other new methods of production. This requires 

 national investment. The counterargument is that the firm presumably selects this research team, out of 

many available at the med school, because their work is atypical and has the greatest commercial potential. 26 Lichtenberg and Siegel (1991) report estimates of the return to R&D based on productivity data for U.S. 

firms. The Lichtenberg-Siegel estimates are based upon a large sample of firms and greatly improved 

estimates of firm productivity. Griliches (2000, pp. 65-66) summarizes some of the main results 

concerning the stock market’s evaluation of firm’s R&D efforts. Hall, Jaffe, and Trajtenberg (2005) show 

that highly cited patents strongly affect stock market evaluation, but less cited patents have little impact. 
17

substantial engineering work. In addition to the capital costs involved, managers and 

workers will have to be trained in the new techniques. Similarly, new products typically 

require very close coordination with marketing specialists. The potential market has to 

be evaluated, and salesmen have to be hired and trained to sell the new product.27 The 

high returns firms apparently earn on research expenditures may partially reflect returns 

to such complementary investments. 

 In addition, returns to private firms may be high because they include a substantial 

risk premium. Mansfield et al. (1971) and Scherer (1999) show R&D projects have 

considerable technical and commercial risk and many projects are not very successful. 

Observed returns to R&D could, in part, reflect a substantial risk premium. 

 Nelson (1988) raised several important issues which should make analysts quite 

careful about accepting and using typical estimates of the rate of return to R&D. Nelson 

points out that R&D and technological opportunity are closely intertwined. Firms with 

high R&D typically have more favorable technological opportunities. Similarly, firms 

with low R&D are likely to face weaker technological opportunities. Consequently, it is 

difficult to determine the extent to which effects attributed to R&D expenditures actually 

reflect the collateral technological opportunities. For this reason, Nelson argues that 

standard regressions, across firms or industries, cannot provide plausible estimates of the 

rate of return to research investments.28,29 

 

27 Mansfield et al. (1971, pp. 112-114) describes the many different types of additional inputs which are 

also necessary in the process of innovation. 28 Griliches (1979, Section 5) also warned about simultaneity problems arising from the mutual 

dependency between R&D investments and past and future expected output. Olley and Pakes (1996) 
18

II.2 Industry (Direct) Returns to R&D. 

 Studies of the direct return to research examine the relationship between R&D and 

productivity within data for different industries. By examining industry data, analysts are 

able to include spillovers between the different firms within an industry. 

 There are important differences between firm and industry returns to R&D.30 As 

Griliches (1979, page 101) remarks, firm knowledge leaks out fairly rapidly, so firm 

R&D depreciates rapidly. On the other hand, much of this knowledge is gained by other 

firms, so social returns depreciate more slowly than firm returns. Similarly, there is a 

greater lag before social returns take effect, and social returns are substantially greater 

than private returns. Consequently, many of the central features of R&D stocks are 

 suggest an important method of addressing such concerns about simultaneity, but do not apply their 

procedure to R&D. Acharya and Keller (2007) usefully apply some of the Olley-Pakes ideas to R&D. 

Such methods are important because they provide estimates of the return to R&D which are much less 

subject to the problem of endogeneity. 

29 If R&D is thought to reflect some other influence, the standard econometric procedure would be to 

attempt to find an instrumental variable which influences R&D growth but is independent of the 

productivity of R&D. Barro (1998, p. 20) comments “R&D spending may respond to exogenous changes 

in productivity growth so that the estimated coefficient on the R&D variable would proxy partly for 

exogenous technological progress. Satisfactory instrumental variables to avoid this problem may not be 

available.” Few studies have estimated the return to R&D using instrumental variables; Jaffe (1986) is 

perhaps the major exception. Lewbel (1997) uses instrumental variables in a study of the effect of R&D on 

patents. 

 Fung (2004) measures intraindustry and intrafirm spillovers from patent citations, and includes 

measures of the overlap in patent citations and the scope (number of patent classes involved in a firm’ 

research) of patents. He finds several of these influences are significant in explaining the effectiveness of 

R&D. Furthermore, allowing for technological opportunity generally increases estimates of the R&D 

elasticity. Fung also considers some of the relationships between his data and the technological 

characteristics of industries. Any progress in this direction is very welcome, but a more fundamental 

understanding of how industry characteristics affect R&D patterns in a broad group of industries is 

necessary before we can understand why technological opportunities differ so widely among industries. 

Klevorick, Levin, Nelson, and Winter (1995) take an interesting initial step in this direction. 30 Many R&D deflators (U.S. Bureau of Labor Statistics (1989); Okubo et al. (2006b)) combine labor costs 

and output price indices, which permits R&D deflators to rise less rapidly than input costs, reflecting 

increases in productivity. However, Griliches (1990) and especially Kortum (1997) show that over time 

greater amounts of research are necessary to generate a new patent. Though there are valid questions 

concerning the use of patents as a measure of research output and how the economic meaning of a patent 

has changed over time, this evidence suggests that the productivity of R&D does not increase over time. 
19

sharply different in industry data than in firm data. If satellite accounts for R&D are to 

include the economic impact of spillovers, the key channel through which R&D affects 

productivity and output growth, national income accountants will have to move beyond 

asset effects to examine spillovers, using alternative values to measure central concepts 

such as depreciation, lags, and the rate of return.31

 Considerable evidence describes leakage of R&D from firms to the broader industry. 

Mansfield (1985) showed information about new technology leaks out to rival firms 

within a year or two. Caballero and Jaffe (1993) similarly find rapid leakage. Jaffe 

(1986) found the pool of nearby research affected technological progress (the number of 

patents) more strongly than it affects private returns (the profits or market value of 

firms).32 

 Nelson’s argument that R&D reflects the presence of collateral technological 

opportunities applies with particular force at the industry level, where major differences 

in technological possibilities are most visible. For example, no one would reasonably 

 

31 Though spillovers are important within an industry, many spillovers of course take place in a broader 

context, to other industries, within a national economy, or internationally. 

 In practice, it is often difficult to determine the rate of depreciation and the lag until research becomes 

effective. For example, a detailed study of 133 firms (Griliches and Mairesse (1984)), which was designed 

to examine the effects of various ways of defining and measuring physical and R&D capital (p. 347), was 

not able to establish definitive estimates of the depreciation rate and the lag (pp. 372-373). 

 Market share structure also affects the difference between firm and industry results. Blundell, Griffith, 

and Van Reenen (1999) show firms with higher market share tend to have a greater number of innovations 

and patents, and the effect of innovation on stock market value is greater for when firms with larger market 

share. Such results show firms with larger market share are able to appropriate a larger proportion of the 

industry gains to R&D. 

32 Baumol (2000) emphasizes that the different firms within an industry often use R&D to compete on the 

basis of product quality, and that the cumulative nature of progress ensures that product quality improves 

greatly over time. As Sena (2004, p. F314) summarizes Baumol’s argument, “spillovers and voluntary 

dissemination allow technological knowledge to spread in the economy so as to increase productivity of 

other firms and this way guarantee the continuous growth and improvement in living standards Western 

economies have experienced in the last two centuries.” 
20

expect productivity growth to become as rapid in lumber as it is in computers if R&D 

intensity in lumber were raised to the levels prevalent for computers. Yet, that is what 

the usual cross-industry regressions assume. Nelson recommended that the return to 

research should be determined not from regressions across firms or industries, but instead 

from careful study of the returns to individual innovations. Subsection II.5 examines 

rates of return obtained from innovation studies. 

II.3 Estimates of Indirect Returns to R&D – Downstream Analyses of R&D. 

 The notion of complementary investments has been important for a long time in the 

understanding of indirect returns to R&D. For example, it has long been the case that, 

when a new computer is introduced, the purchasing firm must deploy considerable 

resources to use the new equipment effectively. Bresnahan and Greenstein (1996) 

describe such complementary investments as coinvention, and Bresnahan (1999) 

emphasized firms must adjust their organizational structure and their work processes, 

which is a long and slow procedure, to take full advantage of the new technologies. 

 In recent years, economists have begun to pay far more attention to the idea that 

new technology requires very substantial complementary investments. Brynjolfsson, 

Hitt, and Yang (2002) argue that such complementary investments are very large. They 

show that financial markets valued a dollar’s worth of computer capital as ten dollars. 

Other kinds of investments do not have such large effects in the financial markets. The 

authors argue that the great effect which computers have on firm financial value occurs 

because large complementary investments, in such areas as software, organizational 
21

redesign, and worker training, are typically made together with the purchase of 

computers. As they point out, such adjustments eventually extend to many fundamental 

characteristics of the firm, such as the extent of centralization or decentralization of 

decisions, patterns of work flow, work compensation and incentive patterns, relationships 

with customers and suppliers, and even corporate culture. Expenditures on improving 

business practices of this type are typically expensed. As Brynjolfsson, Hitt, and Yang 

(2002) argue, if expenditures in these areas increase substantially with computer 

spending, and are a source of unmeasured investment and value to the firm, then the 

observed increase in firm value with computers can provide an estimate of the associate 

increased investment in intangibles. Bresnahan (1999) also provides a very useful 

discussion of the ways in which organizations have to restructure in order to use new 

technology more effectively. Finally, Brynjolfsson and Hitt (2003) have recently 

reported that the observed “return” to computer investments, at the firm level, grows 

steadily over time, which they interpret as ever increasing investment in complementary 

assets.33 

 The clear importance of complementary assets makes it far more difficult to 

determine the appropriate rate of return to R&D. If downstream complementary 

investment is substantial, it becomes very difficult to determine how much of the 

 

33 Bloom, Sudun, and Van Reenan (2006) provide important support for the idea that corporate knowledge 

of information technology applications is central by showing that, in Great Britain, U.S. multinationals are 

more productive than non-U.S.multinationals or domestic firms, and that these productivity advantages are 

associated with higher returns to information technology. Furthermore, these high returns to information 

technology are greatest in sectors such as trade and finance where the U.S. productivity advantage over 

Europe, as measured within industry data, has grown most rapidly, 
22

observed downstream returns are attributable to indirect R&D and how much is due to 

the many different forms of complementary investment. 

Does indirect R&D reflect the presence of measurement error

 Griliches has pointed out (Griliches (1992)) that observed indirect returns to R&D 

could represent either measurement error or true spillovers, which are ideas borrowed by 

one research team from another.34 In practice, as many authors have pointed out, the line 

between measurement error in prices and genuine technology transfer is difficult to 

distinguish. For example, when an aircraft manufacturer prepares a new plane, they 

consult carefully with customers, adapt the plans so as to ensure consumer satisfaction, 

and spend considerable resources on training airlines to use the new aircraft. All these 

mechanisms create genuine technology transfer. When statisticians create a price for 

aircraft, no matter how detailed the specification for an airplane is, such detailed 

characteristics of a sales package are not likely to be included. A single transaction can 

therefore represent both technology transfer and measurement error in prices. 

 

 Nevertheless, there is important evidence that a lot of the indirect returns to R&D 

reflect measurement error. Griliches and Lichtenberg (1984a) present a model in which 

errors in the price of equipment or the price of materials are related to the R&D intensity 

of the sector supplying these goods; the underlying logic of their model implies that the 

indirect effects of R&D primarily represent measurement error. In addition, Gordon 

(1990) demonstrated that equipment prices for highly research intensive capital goods 

 

34 Measurement error occurs if the price of output, in an industry such as computers, does not fully reflect 

improvements in the quality of output. The purchaser then obtains greater quality benefits than the 

measures of price suggest. 
23

contain substantial measurement error. More recently, Greenwood, Hercowitz, and 

Krusell (1997) argued that a declining relative price of equipment, heavily influenced by 

Gordon’s estimates of the quality-corrected price of equipment, has been an important 

ingredient in growth. 

 If observed spillovers associated with indirect R&D primarily reflect measurement 

error in prices rather than the transmission of ideas, these returns cannot be used as a 

contributor to productivity growth and as a source of output growth. As Jorgenson 

(1966) showed long ago, if a correction is made to increase the growth of output in a 

poorly measured capital goods sector, this adjustment will increase output and multifactor 

growth, but the corresponding increase in higher quality capital input, purchased by 

customers, will reduce multifactor productivity. The two effects roughly offset each 

other, and there is little net effect on multifactor productivity growth. It is therefore an 

important issue whether the spillovers associated with indirect R&D reflect only 

measurement error. In the likely instance in which a large proportion of indirect R&D 

spillovers reflect measurement error, this portion of the spillover cannot be used to 

explain multifactor productivity growth. When Fraumeni-Okubo (2005, Table 1) include 

indirect rates of return in their estimates of the overall return to R&D, they implicitly 

assume that none of the spillovers associated with estimates of the social return to R&D 

reflect measurement error, which is not likely to be correct (Gordon (1990)). Their 

reference to the possibility of measurement error (footnote 9) does not sufficiently warn 

the reader that, if measurement error is important, most of the estimates of the indirect 

return to R&D should not be used to help determine the overall return to R&D. 
24

 In view of these considerations, estimates of indirect returns are subject to important 

limitations. Heavy downstream complementary investments distort the picture, and there 

is evidence of considerable measurement error, which implies that any substantial net 

effect on productivity is questionable. In view of these difficulties, one has to be 

extremely careful about adopting estimates of the rate of return to R&D which rely 

heavily on estimated indirect returns. 

II.4. The Spillover of Ideas. 

 Early work on R&D concentrated on the returns to firms and industries. However, 

more recently, spurred by comments in Griliches (1979; 1992), attention shifted towards 

true spillovers of ideas. Many studies have used detailed information from patent records 

to trace the evolution of ideas. 

 

 Jaffe (1986; 1988) examined the effects of knowledge spillovers between firms, 

where intrafirm spillovers depended on the similarity of firm’s patent portfolios. Not 

surprisingly, the spillover of nearby R&D had a greater impact on technical progress, as 

measured by patents, than on profits or stock market value. Verspagen (1997a; 1997b) 

and Frantzen (2002) used detailed information from patent records to describe knowledge 

spillovers between countries and industries.35 

 

35 These studies examine the effect of R&D in the domestic industry, R&D in related industries, foreign 

R&D in the same industry, and foreign R&D in associated industries. Though an overall R&D effect is 

clear, the more detailed measures often face collinearity difficulties (Verspagen (1997b). 

 In other work, Park (2004) examines international and intersectoral spillovers of R&D, and 

concentrates on spillovers to production outside manufacturing, an important issue which deserves further 

consideration. Moretti (2004) examines human capital spillovers within metropolitan areas using several 

measures of technical connection between different industries obtained from the R&D literature. He finds 
25

 Jaffe and Trajtenberg (2002) carried out extremely comprehensive work which 

provides detailed information on each individual U.S. patent from 1963 to 1999. Their 

work emphasizes the forward citations gained by each patent.36 In conjunction with 

evidence from Trajtenberg (1990), Harhoff, Narin, Scherer, and Vopel (1999), and 

especially from Hall, Jaffe, and Trajtenberg (2005), this line of work shows how 

important forward citations are.37

 Jaffe and Trajtenberg (2002) include a diskette, which makes their detailed data on 

United States patents easily accessible. Their generosity in making these data available 

has already led to a broad literature (Peri (2005); AlAzzawi (2004)) which has begun to 

make important contributions to a variety of issues.38 Somewhat fortuitously for the 

purposes of the present discussion, the release of the Jaffe-Trajtenberg data provides an 

example of the vast downstream spillovers potentially associated with important 

technological progress.39

 Though much of the literature on spillovers concentrates on spillovers across 

industries or countries, work has also begun to examine spillovers in many other 

 input-output connections and Jaffe’s measure of the similarity between industry technologies work better 

than interindustry patent citations. 

36 Forward citations are citations a patent earns in the future. Backward citations are citations a patent 

application makes to prior work. 

37 Lanjouw and Schankerman (2004) consider the relative importance of several indicators of patent 

quality, including forward cites, backward cites, and the number of claims made in each patent. All three 

of these effects have some importance. 38 Almeida (2004) analyzes highly detailed information on the identity of individuals who have filed 

important patents to study the effect of labor mobility on technical change. Almeida’s work on individual 

inventors illustrates the rich potential of the more detailed information included in each patent. 

39 The availability of the Jaffe-Trajtenberg data is an example of within industry spillover, if the relevant 

industry is defined to be economic research. Clearly, the importance of within industry spillovers depends 

on the definition of an industry. 
26

circumstances. Jaffe, Fogarty, and Banks (1998) studied how research carried out by 

NASA spilled over to industry. Adams, Chiang and Jensen (2003) examined how 

research conducted in Federal research laboratories, which accounts for 14 percent of 

total United States research expenditures, spilled over to private firms. Building on 

Mansfield (1995), Adams (2004) investigated how research conducted in specific 

university departments affected industrial users. Darby and Zucker (2003) described how 

star scientists have been influential in transferring ideas to biotechnology firms.40 It is 

useful to understand the transfer of ideas through all these different types of linkages. 

These articles show that, beyond the firm to firm transfers that comprise the core of the 

R&D literature, substantial technology is also transferred from government or 

universities to private firms. 

IV.5 Evidence on Private and Social Returns from Studies of Individual Innovations. 

 In view of the difficulties associated with estimates of direct and indirect returns 

(Subsections IV.2 and IV.3 above), it is tempting to follow Nelson (1988) and obtain 

private and social returns to R&D from studies of individual innovations. The major 

article which examines individual innovations is Mansfield et al. (1977). 

 There are two problems with relying on Mansfield’s results. First, the study included 

only 17 innovations. However, the National Science Foundation soon replicated 

Mansfield’s work (Tewksbury, Crandall, and Crane (1980); Nathan Associates (1978)). 

The three studies together consider 57 innovations. 

 

40 See also Zucker, Darby, and Armstrong (1998). 
27

 Second, Mansfield et al. (1977) emphasize the median rate of return to individual 

research projects (25 percent private returns and 56 percent social returns). If one is 

interested in the return to a typical scientific project, the median rate of return is relevant. 

However, to understand the effect of R&D on productivity and output growth, the mean 

project return is relevant. As Scherer (1999, Chapter 5) shows, most research projects are 

not particularly successful, but a few very large successes drive total returns. If one looks 

only at median returns, the very large effects which the most successful projects have on 

output and productivity growth will be missed. 

 In all 57 innovations, the median private return to research is estimated to be 28 

percent, and the median social return is 71 percent. This information suggests social 

returns exceed private returns by 43 percent. The three innovation studies include 7 

observations where the private return is negative, and 5 where social returns are negative. 

The studies do not report specific losses for failing innovations. Assuming negative 

returns are losses of 50 percent, average private returns are 32 percent, and average social 

returns, boosted by 11 innovations where the reported social return is greater than 150 

percent, are 87 percent.41 

 There is one potential problem with these innovation data. Scherer (1999) showed 

most innovations are typically not profitable. However, the private rate of return was 

negative for only 7 of the 57 innovations. The low incidence of negative returns suggests 

that the innovations considered may not be representative. 

 

41 Social returns of the magnitudes mentioned in this paragraph imply that private returns represent 

considerably less than half of the total social return. 
28

 In summary, Mohnen (1996, p. 50) concluded, based on a broad overview of the 

R&D literature, that “On average, the social return to R&D exceeds the private return by 

50 to 100 per cent.” The innovation studies provide important further evidence that 

social returns are very large and exceed private returns by a substantial margin.42 

IV.6 The Fraumeni-Okubo Summary of Evidence on the Rate of Return to R&D.

 Fraumeni and Okubo (2005, Table 1) recently selected nine studies to determine the 

rate of return to privately funded R&D. 

Table 1. Evidence on the Rate of Return to Private R&D. (from Fraumeni and Okubo) 

 Author (year) Private return Social return 

Sveikauskas (1981) 7-25 % 50 % 

Bernstein-Nadiri (1988) 10-27 11-111 

Bernstein-Nadiri (1991) 15-28 20-110 

Nadiri (1993) 20-30 50 

Mansfield (1977) 25 (median) 56 (median) 

Goto-Suzuki (1989) 26 80 

Terleckyj (1974) 29 48-78 

Scherer (1982, 1984) 29-43 64-147 

 Five of the nine papers (Sveikauskas (1981), Goto-Suzuki (1989), Terleckyj (1974), 

and Scherer (1982, 1984)) are industry studies, and report the return to research 

conducted “Within” the industry and the return to R&D “From Outside”, that is R&D 

carried out by other industries.43 Although some text (Goto and Suzuki (1989, p. 561) 

 

42 Wolff (1997) concludes the social return is 53 percent and the private return is about 10 to 12.5 percent, 

which also implies social returns exceed private returns by 40 percent. 

43 Section III of Goto-Suzuki reports estimates of the private return to firms, but Sections IV and V of their 

paper, which deal with social returns, are based on industry data. 
29

interprets these coefficients as private and social returns, “private” returns here reflect 

industry returns, not firm returns. Industry returns correspond to firm returns only if 

there are no spillovers within an industry.44 

 Bernstein and Nadiri’s (1988, 1991) work is slightly different. They analyze 

industry data, but remove the capital (1988, page 431) and labor and materials (1991, 

page 37) used in research from the BLS or NIPA factor inputs typically used to study 

U.S. productivity. By making this adjustment, they are able to estimate total returns to 

R&D rather than just R&D spillovers.45 However, the coefficients they estimate at the 

industry level show the sum of the private return to the firm undertaking R&D investment 

plus spillovers to other firms in the industry. These returns are not the same as “private 

returns”, the total returns to an individual firm undertaking research, as described in 

Mansfield et al. (1977). 

 

44 Fraumeni and Okubo (2005, Table 1) list the private and social returns to R&D reported in these studies. 

They attribute the numbers to a Council of Economic Advisers file, which no longer exists on the Web. 

Joseph Stiglitz, then Chairman of the Council, distributed a handout based on this file during a talk in 

Washington. Fraumeni and Okubo report the Council’s summary accurately. However, the columns of the 

Council table were not properly labeled. As discussed in the text, only Mansfield et al. (1977) reports a 

private rate of return, in the traditional sense of the total returns to a private firm. Some of the ambiguity 

comes from Griliches (1992, Table 1, part II), which combines information on the private and social return 

to R&D with parallel information on the direct and indirect return within a single table. The text of that 

paper (page S43) comments that the estimated social rates of return look surprisingly uniform, but does not 

emphasize that many of the rates of return reported in the left column of Table 1 (listed as Within and From 

Outside, respectively) include elements of social returns (the within industry spillover, and the excess 

return, which exceeds the costs of R&D) and does not represent the traditional private return to firms. 

(Griliches (2000, pp. 60, 61, and 70) shows returns to R&D are considerably greater in industry data than in 

firm data.) 

45 Current BEA work on R&D (Schultz (2006)) now removes factor expenditures on R&D from factor 

inputs, using recently expanded NSF data on the composition of research costs in each industry. This 

important advance permits BEA to estimate the total return to research, rather than just the spillover 

component of returns. For a discussion of why standard procedures estimate only the spillover effect see 

U.S. Bureau of Labor Statistics (1989, page 36). 
30

 Nadiri (1993) summarizes results from many different studies, on both a firm and 

industry basis. The only study on the Fraumeni-Okubo list which actually estimates 

private and social returns is Mansfield et al. (1977), which is fundamentally different 

because it measures the return to individual innovations rather than firm and industry 

regressions. Except for Mansfield, the studies cited do not provide information on the 

private and social rates of return to R&D. 

 In view of these many difficulties, what R&D expenditures should be included as 

investment and what rate of return should be attributed to them? First, in industry, all 

privately financed research should clearly be counted as investment. However, the 

evidence indicates federally financed research in industry, on net, does not have a 

positive return, so such expenditures probably do not qualify as investment. Second, 

because of the issues of relevance to growth and double counting discussed in Section I, 

only a small proportion of the research financed by government or universities should be 

classified as investment. 

 Third, the studies Fraumeni-Okubo (2005) list in their Table 1 are far too heavily 

weighted towards industry studies of direct and indirect returns. Such estimates depend 

much too heavily on indirect returns to R&D, which are unreliable because they depend 

on the amount of complementary investment, and at least partially reflect measurement 

error, so that the estimated indirect effects are probably not a genuine effect on 

productivity. Fourth, because of the many difficulties with the regression estimates it is 

probably useful to emphasize rates of return obtained from the innovation studies, which 
31

also indicate that social returns are very large and considerably exceed private returns. 

On balance, private returns of 25 percent and social returns of about 65 percent, which 

more than double the private return, seem reasonable. However, these extremely high 

returns are relevant only for privately financed research. 

III. R&D Stocks on an Industry Basis. 

 

 In the growth accounting literature, residual income, which remains after all other 

factors of production are compensated, is generally attributed to capital. The standard 

treatment of capital in growth accounting, due to Jorgenson and Griliches (1967), first 

removes payments to labor and materials from income, and then, using the HallJorgenson (1967) procedure, assigns the sum which remains, property income, to specific 

capital assets. These procedures first allow for depreciation, taxes, and other costs of 

capital, and then allocate the rest of capital income to the internal rate of return, or capital 

profit. 

 Much evidence suggests that observed profit income is not just a return to capital, but 

also reflects returns to research and development and other intangible assets. For 

example, Grabowski and Mueller (1978) examine a sample of 86 firms which conduct at 

least some R&D. They report (p. 342) the overall variance in profit rates was reduced 

approximately in half when R&D was capitalized rather than expensed. They conclude 

that the after-tax return to R&D is between 15 and 20 percent, considerably above the 

rate of return earned on other assets, but comparable to the returns reported in Mansfield 
32

et al. (1977). The Grabowski and Mueller study clearly shows that some of the income 

typically included in the return to capital actually represents a return to R&D. 

 Recently, economists have discussed investments in many types of intangibles which 

extend far beyond R&D. Corrado, Hulten and Sichel (2003) estimate that expenditures 

on intangibles in the United States were $1221 billion, annually, in the United States 

from 1998 to 2000. R&D expenditures, as defined by the National Science Foundation, 

were $185 billion, or only about 15 percent of the total. Investments in knowledge in 

other areas, such as finance, movies, and books, which the NSF does not count as 

research because they are not based on an explicit scientific or technological field, were 

estimated to be $199 billion.46 Among other items, computer software accounted for 

$154 billion, advertising for $254 billion, employee training for $123 billion, and 

management improvement for $306 billion. R&D accounts for only a small share of the 

amount firms spent, beyond capital expenditures, to increase future output.47 

 The Multifactor Productivity program of the Bureau of Labor Statistics currently 

includes plant, equipment, inventories, land, and software as capital assets, and calculates 

the internal rate of return, service price, and income paid for each asset. A separate 

internal rate of return and industry-specific asset service prices are calculated for 56 

 

46 The National Science Foundation publication Research and Development in Industry does not include 

R&D in the social sciences or psychology, so research in financial economics does not appear in these data. 

47 Many of the assets Corrado, Hulten, and Sichel (2003) consider depreciate considerably more rapidly 

than tangible capital and R&D, so the proposed new items account for a smaller proportion of the overall 

capital stock than these figures on investment indicate. 
33

different industries. If R&D is to be treated as an investment, it would be natural to 

expand the BLS calculations, on an industry basis, to include R&D as a further asset.48 

 Unfortunately, it is difficult to determine the relevant R&D stock within each 

industry in the United States. As Scherer (2003) discusses, in the U.S. most data on R&D 

are collected at the firm level. Many large firms invest substantial sums in R&D. 

However, these firms frequently operate in many different industries, and it is not clear 

how much of each firm’s total research portfolio supports production in any particular 

industry.49 As an illustration of the difficulties involved, Wolfe (2003) reports the U.S. 

National Science Foundation assigns large amounts of R&D to the trade industry, even 

though relatively little research actually takes place in trade. The problem occurs because 

all research conducted by a firm is assigned to the one industry in which its payroll is 

greatest. If a pharmaceutical firm has many sales representatives, its research efforts 

could well be assigned to trade, even though all the research actually takes place in 

pharmaceuticals. 

 Because these procedures assign all research conducted by a firm to a single 

industry, current National Science Foundation data are not accurate enough to create a 

reliable measure of R&D stocks within each of the BLS industries.50 In my judgement, it 

 

48 The BLS calculates a separate internal rate of return for each of 56 industries included in the nonfarm 

private business sector. To extend these calculations to R&D requires R&D stocks for each of these 56 

industries. 

49 Brown, Plewes, and Gerstein (2004) discuss the limitations of available measures of R&D in specific 

industries in considerable detail. 

50 The Bureau of Economic Analysis faces similar issues in establishing industry R&D stocks. Carson, 

Grimm, and Moylan (1994), and much of the rest of the R&D literature, has used the existing NSF data on 

industry R&D expenditures to create industry R&D stocks. 
34

is necessary to modify the NSF data on industry R&D expenditures considerably before 

they can provide a sound measure of R&D assets in each industry. 

 A potential method of assigning R&D spending conducted by individual firms to 

specific industries could follow the well-established procedures which the Bureau of 

Economic Analysis currently uses to allocate profits earned by firms to specific 

industries. The BEA takes Internal Revenue Service measures of the profits earned by 

firms classified in each industry, and allocates these profits to establishments in particular 

industries on the basis of data showing the industries in which these firms actually 

employ workers, as determined from the Enterprise Statistics. 

 Similar procedures are likely to improve the accuracy of measures of the R&D 

actually committed to each industry. A separate allocation can be conducted for every 

firm, allocating that firm’s research in proportion to its own industry distribution of 

employment or payroll. Furthermore, firm R&D could be assigned to particular 

industries not only on the basis of employment or payroll, but also on the basis of the 

intensity of scientific and technical employment within each industry. Through such a 

methodology, trade, where scientific input is typically low, would for that reason be 

assigned less of a firm’s research than pharmaceuticals, where scientific input is typically 

high.51 A simple allocation procedure of this type is likely to provide better estimates of 

 

51 As an example, each firm’s proportion of its work force in a given industry, si, could be multiplied by 

the proportion of technological employment in that industry in general, ti. Then, that firm’s R&D 

expenditures could be allocated to specific industries in proportion to siti as a share of the firm’s total siti

across all i industries. If R&D is allocated by payroll, in the second stage industry totals would have to be 

adjusted to reflect the technological employment/payroll or technological payroll/payroll ratios. 

 In a slightly different, but probably preferable, methodology, each firm’s research expenditures can be 

regressed on its payroll in each relevant industry. The resulting industry coefficients then provide an 
35

the R&D actually occurring in each industry than those obtained by assigning each firm’s 

R&D solely to one industry. Furthermore, since a large number of firms contribute to 

production in any given industry, the proposed alternative procedure is less likely to have 

problems with disclosure limitations.52 The procedures proposed here would probably 

make it possible to publish R&D estimates for a larger number of industries, which 

would help overcome one of the major limitations of current NSF industry R&D data.53

 

 Once the distribution of R&D across industries is better understood, more reliable 

information on the industries in which R&D actually occurs can in turn be used to 

determine the industries in which R&D is actually utilized. The literature (Scherer (1982, 

1984); Verspagen (1997a; 1997b); Moretti (2004)) has used input-out relationships, 

information from patent applications, and careful analysis of individual patents to 

determine the specific industries in which R&D spillovers occur. 

 The Bureau of Labor Statistics currently uses an interesting framework to understand 

the role of R&D spillovers in the aggregate economy. Spillovers do not provide income 

to any particular asset, and are not included within the data on factor inputs and factor 

earnings which determine the portion of growth attributable to specific inputs. Instead, 

aggregate spillovers are included “below the line”, as one of the determinants of observed 

 estimate of research intensity in each industry. It would be of interest to examine how closely such 

industry coefficients match actual measures of scientific or technical employment in each industry. The 

procedure suggested in the present paragraph determines research intensity in each industry from a 

statistical procedure, rather than by assumption, and utilizes the highly detailed data available for each firm. 

Because more data are utilized, this variant of the methodology seems likely to provide estimates of 

research intensity for a larger number of industries. 

52 For example, if each firm produces output in five industries, the data cell for a typical industry would 

contain information from five times as many firms. 53 I plan to construct and analyze alternative measures of industry R&D, prepared along the lines 

discussed above. 
36

multifactor productivity growth. Such procedures are helpful in evaluating the role of 

spillovers in national data. However, further information on the industry distribution of 

spillovers is necessary to extend this approach to specific industries. 

IV. International R&D Spillovers. 

 As evidence presented below indicates, even for the United States, a very large and 

highly advanced economy, foreign R&D plays an important role in technical progress. 

Most of the other countries in the world, which are much smaller and less technically 

progressive, are far more dependent on foreign R&D. Consequently, most of the 

statistical agencies in the world will have to understand and evaluate how foreign R&D 

affects their economies in order to include the full effect of R&D in their accounts. 

 R&D is heavily concentrated in a few developed countries, essentially in the 

OECD.54 Even within the OECD, a few relatively large countries, like Germany, Japan, 

and the U.S., account for a large proportion of R&D.55 Once R&D is included in the 

national income accounts, economists will have to provide the underlying information on 

how R&D in the leading countries affects production in small rich countries or in the 

developing world. 

 

54 The OECD countries had a particularly large share of world R&D in the 1970s, 1980s, and 1990s. 

However, in very recent years R&D has increased sharply in several countries outside the OECD, notably 

China and India. 

55 For example, in 1995 the United States, Japan, and Germany accounted for more than two-thirds of 

OECD R&D expenditures, and the G7 countries together accounted for about 85 percent of the total. Data 

are from the OECD Science, Technology, and Industry Scoreboard: 2003. 
37

 There are many potential channels through which the undoubted technological 

advantages of the most advanced countries can be transmitted to less wealthy nations. 

One branch of the literature emphasizes the mere presence of international trade (Coe and 

Helpman (1995)). Other analyses emphasize the presence of multinational companies 

(Gorg and Strobl (2001)) or the role of foreign domestic investment (Borensztein, De 

Gregorio, and Lee (1998), Aitken and Harrison (1999)).56 The transmission of ideas 

(AlAzzawi (2004)), through such mechanisms as the scientific or technological 

literatures, is another potentially important pathway. Of course, in actual practice many 

or all of these potential channels of transmission are likely to be influential. Much work 

still remains to be done to sort out how these potential influences interact and to 

understand the particular circumstances under which each is important.57

 Even among rich countries, there is a distinction between the largest countries, such 

as the U.S., Germany, and Japan, which conduct large amounts of research, and small 

countries which perform much less research. Within the research leaders, spillovers 

within an industry and across industries tend to be very important. In smaller countries, 

many of the equivalent effects come into existence through foreign trade spillovers.58

 

56 Although much of the literature concentrates on whether technology from multinationals spills over to 

domestic production, multinationals of course make a contribution if they produce at a higher level of 

productivity than domestic firms. 

57 Recent studies have begun to investigate links between different facets of technology transfer. For 

example, AlAzzawi (2004) examines the extent to which spillovers of knowledge, as measured by patent 

citations, are associated with foreign domestic investment. Branstetter (2000) examines whether Japanese 

investment in the United States is a channel of knowledge spillovers to Japanese firms. 

58 Tables 4 and 5 of Coe and Helpman (1995) support the statements made in this paragraph. As in most 

estimates of this type, spillovers from the U.S., Germany, and Japan are larger than those from other 

countries. Coe-Helpman also find domestic R&D is more important than foreign R&D in large countries, 

but foreign R&D is more important than domestic R&D in most small countries. 
38

 One branch of the empirical literature examines research spillovers among advanced 

(OECD) nations. Coe and Helpman (1995) emphasize the volume of foreign trade as a 

key to research spillovers. Their work also includes imports as a proportion of GDP, 

which permits technology transfer to vary with the importance of trade. In later work, 

Lichtenberg and van Pottelsberge de la Potterie (1998) suggest a better measure of R&D 

flows, and Funk (2001) and Kao et al. (1999) clarify the econometric issues involved. 

Despite these improvements, Coe-Helpman (1995) remains the classic article which 

demonstrates the potential importance of international R&D spillovers. 

 Xu and Wang (1999) is a particularly useful study of R&D spillovers within the 

OECD. They show R&D in capital goods affects productivity growth, but R&D 

contained in other forms of trade does not. Xu-Wang include domestic R&D stocks as 

well as a proxy for the extent of the disembodied flow of information (a distance 

weighted, or unweighted, measure of other countries R&D stocks) in addition to the 

R&D contained in capital goods. The broad range of variables allows them to determine 

the importance of R&D transmitted through each of these channels. Xu and Wang (1999) 

is one of the most insightful and helpful contributions in the literature because they report 

estimates of returns obtained through each mechanism.59

 

 

59 Verspagen (1997b) similarly concludes that R&D spillovers embodied in purchased inputs and 

knowledge floating freely across international borders both play a role in technology transfer across 

countries. Like Xu and Wang (1999), Verspagen (1997b) shows R&D spillovers from the large technology 

leaders have the greatest impact on other nations. 

 Griffith, Redding, and Van Reenen (2004) integrate R&D with international technological 

convergence. They demonstrate that, in additional to the usual R&D effect (observed at the industry level), 

there is convergence (in the sense that country-industry observations at a lower level of productivity tend to 

catch up), and that R&D permits the successful absorption of foreign technology. Keller (2002) studies 

R&D spillovers from the largest countries to smaller OECD nations. 
39

 Another strand of the literature considers R&D transfers to countries outside the 

OECD, typically developing nations which conduct very little R&D. Coe, Helpman, and 

Hoffmaister (1997) is the original contribution in this direction. Schiff, Wang, and 

Olarreaga (2002) and Connolly (2003) conduct more recent work. Schiff, Wang, and 

Olarreaga (2002) find R&D imported in capital or materials from Northern countries 

increases productivity in Southern industries, especially in R&D intensive industries. 

 Many studies of technology transmission to developing countries (Borensztein, De 

Gregorio, and Lee (1998); Connolly (2003)) examine data for the aggregate economy. 

More information could be brought into play if economists constructed more reliable 

measures of industry productivity growth in different countries.60 

 The effect of technology transfer on developing countries will eventually have to be 

understood on the basis of highly detailed information on firms and establishments. 

Muendler (2004) recently studied the type of information which is needed.61 His work on 

 

60 Two recent studies illustrate both the potential of international comparisons based on detailed industry 

data and the need for better measures of productivity. Savvides and Zachariadis (2004) examine the effects 

of research contained in foreign capital goods, the amount of capital goods imports, and foreign investment 

on productivity growth in manufacturing. However, economy wide deflators, rather than data specific to 

manufacturing, are used to measure real ouput. Similarly, Schiff, Wang and Olarreaga (2002) examine 

how R&D imports affect productivity growth in 16 manufacturing industries in 25 developing countries. 

Output data are expressed in U.S. dollars and deflated by the U.S. GDP deflator. It is questionable whether 

this procedure generates productivity measures which are as reliable as studies which use industry specific 

output price deflators for each country. 

 The International Comparisons of Output and Productivity (ICOP) project at the University of 

Groningen has, for many years, measured international productivity differences based on detailed 

information on unit values in different countries. 

61 Hallak and Levinsohn (2004) similarly recommend the use of highly detailed micro data, rather than 

aggregate country data, in the analysis of the closely related issue of whether increased amounts of foreign 

trade bring a positive effect to the growth rate. As in the present review, they recommend greater emphasis 

on the analysis of, and discrimination between, the many different channels through which growth effects 

may operate. Hallak-Levinsohn also argue that different channels are likely to be influential in different 

circumstances. A recent review (Keller (2004)) also emphasizes the need for detailed data, as well as the 

usefulness of case study evidence. 
40

productivity in Brazilian firms included measures of the foreign equipment and materials 

available to each firm. He concluded foreign import competition was more important 

than foreign technology.62 If further work, especially with detailed establishment data on 

other countries, confirms these results, technology may be less important than previous 

discussion has suggested. In that event, greater weight will have to be attached to 

product market competition, as emphasized in Parente and Prescott (1994; 1999) and 

Lewis (2004). It is worthwhile to be reminded that technology transfer can be much 

more effective when other economic conditions are supportive.63 

 On balance, there is widespread international transmission of knowledge associated 

both with the imports of R&D-intensive capital equipment (Xu and Wang (1999), Coe, 

Helpman, and Hoffmaister (1997), and Caselli and Wilson (2004)) as well as R&D 

included in materials as well as capital equipment (Schiff, Wang and Olarreaga (2002)). 

This international transmission of R&D typically has a favorable effect on productivity 

growth. One interesting study finds strong benefits associated with R&D intensive 

materials (Lichtenberg and Virabhak (2002)). 

 In addition to Muendler (2004), several further studies examine detailed data on production in 

developing nations. Basant and Fikkert (1996) analyze panel data for Indian firms between 1974 and 1982. 

India appears to be a developing country in which many firms conduct their own R&D. They emphasize 

foreign purchases of technology, as well as the impact of domestic R&D, and construct a foreign R&D 

spillover measure by weighting R&D in eight wealthy economies by each country’s relevance to India, as 

determined by patents granted in India. 

 In a production function study, Bartel and Harrison (2005) compare the productivity of public sector 

and private sector production in Indonesia. Among other topics, they consider the effect which foreign 

ownership has on productivity. Blalock and Veloso (2006) examine the effect of imports on productivity in 

Indonesian data. All this work illustrates the usefulness of highly detailed datasets describing productivity 

growth over time. See also Haskel, Pereira, and Slaughter (2007) for the United Kingdom. 62 In further evidence supporting the Parente-Prescott and Lewis view, Schiff and Wang (2004) show that, 

in North-South trade, openness to trade, as measured by the amount of trade, has a greater impact on 

productivity growth than the knowledge (R&D) content of a unit of trade does. 

63 Some scholars emphasize countries gradually have to develop the capacity to use modern technology. 

Nelson and Pack (1999) present such a viewpoint, and compare the results with growth accounting. 
41

 There is also substantial transmission of knowledge not specifically associated with 

factor inputs (Xu and Wang (1999)). Such disembodied knowledge flows are often 

highly localized (Peri (2005), Maursith and Verspagen (2002)). The importance of 

distance may change greatly over short periods of time (Keller (2002)). 

 A large advanced economy such as the U.S. generates most of its own technical 

progress. Foreign R&D could be most influential if it allowed U.S. research to improve 

more rapidly. However, it is difficult to evaluate the importance of foreign ideas. As 

U.S. Bureau of Labor Statistics (1989, page 6) remarked: 

“A further issue is whether foreign research investment should be included. Clearly, as 

foreign technological levels have approached U.S. levels and as American multinational 

corporations have conducted more research abroad, foreign R&D has become more 

relevant to U.S. firms. However, the relative weight to be attached to a unit of foreign 

research and how this may have changed over time are unclear.” 

 Data on patent citations now make it possible to determine the relative importance of 

foreign research, and how this changes over time. Consider all U.S. patents granted to 

inventors located in the United States. Such patents arguably provide a good description 

of U.S. technical progress each year. Table 2 shows how often these U.S. patents cite 

U.S. and foreign research.64 

 

64 I thank Anastasiya Osborne for programming the large data bases containing these patent data. 

 If one looks only at citations of foreign work patented in the U.S., it is necessary to examine how 

much foreign research is patented in the U.S., and how this proportion changes over time (Eaton and 

Kortum (1996; 1999)). However, the data reported in the text include all citations made by U.S. patents, 

regardless of whether the cited patents are U.S. or foreign. If each citation made by a U.S. patent is 

assumed to be of equal value, a simple count of the domestic or foreign origin of citations provides direct 

information on the relative importance of domestic and foreign research. Because large numbers of 

citations are observed each year, differences in the importance of individual citations should cancel out. 

 The available data report the country of cited patents only for patents granted in 1963 or later. We 

estimate the country origin for patents granted prior to 1963 on the basis of time trends in later years. It is 
42

Table 2 Citations of Foreign Patents, in Proportion to Citations of U.S. Patents 1976-2000 

 (for utility patents, year refers to year of application) 

1976 .301 1981 .366 1986 .435 1991 .490 1996 .505 

1977 .314 1982 .389 1987 .447 1992 .503 1997 .510 

1978 .327 1983 .399 1988 .455 1993 .510 1998 .497 

1979 .338 1984 .405 1989 .470 1994 .521 1999 .506 

1980 .356 1985 .426 1990 .473 1995 .552 2000 .525 

Source: computed from files of individual patents, as provided by the U.S. Government 

Patent and Trademark Office. 

 These data suggest that in 1976, in addition to knowledge obtained from U.S. R&D, 

the United States had access to 30 percent further knowledge from foreign research.65 By 

2000, the increment of foreign knowledge increased to 53 percent. 

 U.S. productivity growth accelerated sharply in the late 1990’s, and the productivity 

recovery was sharper in the U.S. than abroad. Table 2 shows the proportion of citations 

of U.S. work declined steadily from 1976 to 1995, but this trend then reversed. Patent 

citations suggest U.S. technology turned a central corner in 1995; the timing is 

remarkably similar to the year in which U.S. productivity growth accelerated. 

 important not to omit cited patents occurring before 1963, which are overwhelmingly of U.S. origin. Early 

versions of this paper reported a greater proportion of foreign citations, because citations to patents 

occurring prior to 1963 were not yet included. 

65 These calculations assume that each citation, whether domestic or foreign, contributes the same 

amount of knowledge to U.S. innovation. The proportion of foreign citations is greater than found in many 

other studies because citations of patents granted outside the U.S are included. For example, in 1976 there 

were 34984 citations of U.S. patents granted to foreign inventors, and 17370 further citations of foreign 

patents. 
43

 If we assume foreign R&D increased U.S. effective R&D stocks by the ratios given 

in Table 2, and foreign knowledge earned the same 30 percent rate of return, foreign 

R&D contributed 0.1 percent a year to 1947-2002 U.S. productivity growth.66 

 A major unresolved question is what happens to returns to R&D in the U.S. and other 

advanced countries as further nations, such as China and India, expand their capability to 

do R&D. So far, most studies conclude R&D in one country increases productivity in 

other countries. However, Luintel and Khan (2004) report foreign R&D reduces 

productivity in the United States. The effect of international competition in technology 

on the returns from R&D is a crucial question which requires much further analysis.67 68

V. Conclusions. 

 Recent decisions to include research and development expenditures in the System of 

National Accounts raise important new questions for statisticians in developed and 

developing countries. Many of the benefits of R&D are not obtained by the original 

investors, but instead leak out to other firms, customers and even other nations. Because 

the asset and spillover influences of R&D have different time horizons, it is useful to 

establish separate “national R&D stocks” for each purpose. 

 

66 Under these assumptions, the 1948-2002 R&D effect increases from .17 percent a year (with the usual 

BLS estimates based on just domestic R&D) to .24 percent Since information on the country of origin of 

citations is available only for 1976 and subsequent years, the productivity calculations mentioned above 

estimate the foreign percent of citations for years prior to 1976. Since information on foreign citations is 

more reliable for 1973-2002, we mention that, in these years, the domestic R&D contribution of .18 percent 

a year to productivity growth increased to .29 percent a year when foreign R&D is taken into account. 

Foreign R&D is important, of course, due to the rapid growth of foreign citations, as reflected in Table 2. 

67 Hall concludes (1993, page 317) that greater competition, much of it foreign, reduced the U.S. private 

return to R&D in the 1980’s, but had less of an impact on social returns to R&D. As R&D increased in 

other countries, the United States perhaps lost some monopoly power over innovation (Freeman (2005)). 

68 In developing countries, technology typically adopts and modifies advances created in the wealthy 

nations, so information on innovations, such as patents, provides a less complete picture of new technology. 
44

 On the basis of the evidence considered, privately financed R&D in industry should be 

treated as an investment and included in the relevant R&D stock. Returns to R&D are 

very high, but these high returns accrue only to privately financed R&D. Many elements 

of university and government research have very low returns, overwhelmingly contribute 

to economic growth only indirectly, if at all, and do not belong in investment. 

 Much remains to be understood about the specific pathways through which R&D in 

advanced nations is transmitted to developing countries. There are many potential 

pathways through which this knowledge may spread. Once R&D is included in the 

accounts, economists will hopefully pay much more attention to understanding exactly 

which channels are effective in transmitting knowledge to poorer countries. 

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