NISTIR 7944

Fingerprint Scanner Affordances

Michelle Steves

Brian Stanton

Mary Theofanos

Dana Chisnell

Hannah Wald
NISTIR 7944

Fingerprint Scanner Affordances

Michelle Steves

Brian Stanton

Mary Theofanos

Information Access Division

Information Technology Laboratory

Dana Chisnell

Usability Works

Boston, MA

Hannah Wald

Booz Allen Hamilton

McLean, VA

September 2013

U.S. Department of Commerce 

Rebecca Blank, Acting Secretary

National Institute of Standards and Technology 

Patrick D. Gallagher, Under Secretary of Commerce for Standards and Technology and Director 
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TABLE OF CONTENTS

1 INTRODUCTION......................................................................................................................................2

2 OVERVIEW AND BACKGROUND........................................................................................................3

2.1 FINGERPRINTING TERMINOLOGY..............................................................................................................3

2.2 USABILITY METRICS ................................................................................................................................4

3 METHOD....................................................................................................................................................5

3.1 MATERIALS ..............................................................................................................................................5

3.1.1 Materials for participant use...........................................................................................................5

3.1.2 Materials for researcher use ...........................................................................................................7

3.2 EQUIPMENT ..............................................................................................................................................7

3.3 PROCEDURE ............................................................................................................................................10

3.3.1 Part 1: Scanning fingerprints........................................................................................................10

3.3.2 Part 2: Collecting participant feedback ........................................................................................12

3.3.3 Part 3: Post-processing of the collected images...........................................................................13

3.4 PARTICIPANTS ........................................................................................................................................13

3.5 RESEARCH QUESTIONS...........................................................................................................................13

4 RESULTS..................................................................................................................................................14

4.1 COMPLETING THE TASK..........................................................................................................................14

4.1.1 Overall print capture success .......................................................................................................14

4.1.2 The capture process - researcher observations.............................................................................15

4.2 NOTICING AND INTERPRETING THE AFFORDANCES.................................................................................16

4.2.1 During the capture process...........................................................................................................16

4.2.2 Diagram labeling..........................................................................................................................20

4.2.3 What guided participants as they used the scanner – self-reported..............................................27

4.2.4 Instructive materials and indicators – helpfulness and clarity......................................................29

4.2.5 Confidence and capture success...................................................................................................30

4.3 WHAT PARTICIPANTS FOUND TO BE CONFUSING.....................................................................................31

4.4 PARTICIPANT-REPORTED LESSONS LEARNED..........................................................................................33

4.5 OTHER EFFECTS......................................................................................................................................34

4.5.1 Effects of subject demographics on capture success....................................................................34

4.5.2 Print quality – threshold and results.............................................................................................35

4.5.3 Number of attempts to make a successful slap.............................................................................36

4.5.4 Effects of software crashes...........................................................................................................37

4.5.5 Effects of scanner height on capture success ...............................................................................37

5 DISCUSSION OF THE OBSERVATIONS ...........................................................................................37

5.1 WILLINGNESS TO EXPERIMENT...............................................................................................................38

5.2 QUALITY THRESHOLD.............................................................................................................................38

5.3 LACK OF CLARITY ..................................................................................................................................38

5.3.1 Instructional poster.......................................................................................................................39

5.3.2 Slap icons.....................................................................................................................................39

5.3.3 LED lights....................................................................................................................................40
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5.3.4 Beeps............................................................................................................................................40

5.4 PULLING IT ALL TOGETHER - TIMING CUES.............................................................................................41

5.5 OVERALL SUITABILITY OF SCANNER FOR SELF-SERVICE USE................................................................41

6 CONCLUSION.........................................................................................................................................41

7 REFERENCES .........................................................................................................................................43

APPENDIX A: USER DEMOGRAPHIC SURVEY.......................................................................................45

APPENDIX B: FINGERPRINT SCANNER DATASHEET .........................................................................47

APPENDIX C: POST-TASK SURVEY...........................................................................................................52
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LIST OF TABLES AND FIGURES

TABLE 1: OVERALL FINGERPRINT CAPTURE SUCCESS RATE ..................................................................................14

TABLE 2: DIAGRAM LABELING SUMMARY ............................................................................................................23

TABLE 3: INSTRUCTIONAL INDICATORS USED BY PARTICIPANTS AND CAPTURE SUCCESS .....................................28

TABLE 4: PARTICIPANT RELIANCE ON INSTRUCTIONAL POSTER AND CAPTURE SUCCESS.......................................28

TABLE 5: PARTICIPANTS' RATINGS OF THE CLARITY AND HELPFULNESS OF THE US-VISIT POSTER .....................29

TABLE 6: PARTICIPANTS' RATINGS OF THEIR CLARITY ON ASPECTS OF THE FINGERPRINT PROCESS.......................30

TABLE 7: PARTICIPANT CONFIDENCE SCORES AND CAPTURE SUCCESS (MEAN + SE) ............................................30

TABLE 8: CAPTURE SUCCESS BY GENDER .............................................................................................................35

TABLE 9: CAPTURE SUCCESS AND AGE (MEAN + SE) ...........................................................................................35

TABLE 10: FINGERPRINT CAPTURE SUCCESS AND QUALITY (NFIQ)......................................................................36

TABLE 11: AVERAGE NUMBER OF SLAP ATTEMPTS AND CAPTURE SUCCESS..........................................................36

FIGURE 1: INSTRUCTIONAL US-VISIT POSTER PROVIDING THE BIOMETRIC DATA CAPTURE PROCESS ....................6

FIGURE 2: DIAGRAM OF SCANNER THAT PARTICIPANTS ANNOTATED......................................................................7

FIGURE 3: FINGERPRINT SCANNER WITH INDICATORS.............................................................................................8

FIGURE 4: SCREEN IMAGE SHOWING POSITIONING OF A RIGHT SLAP ON THE PLATEN..............................................9

FIGURE 5: SCREEN IMAGE SHOWING A COMPLETE SET OF PRINTS AS CAPTURED AND STORED ................................9

FIGURE 6: AN EXAMPLE OF A PARTICIPANT’S SCANNER DIAGRAM WHERE MOST FEATURES ARE LABELED 

CORRECTLY.................................................................................................................................................20

FIGURE 7: AN EXAMPLE OF A PARTICIPANT'S SCANNER DIAGRAM WHERE ONLY SOME FEATURES ARE LABELED 

CORRECTLY.................................................................................................................................................21

FIGURE 8: AN EXAMPLE OF A PARTICIPANT'S SCANNER DIAGRAM WITH MINIMAL LABELING ...............................22
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EXECUTIVE SUMMARY

Under the United States Visitor and Immigrant Status Indicator Technology (US-VISIT)

program, the Department of Homeland Security (DHS) collects biometric information from

foreign nationals entering the country. Foreign nationals are required to – among other things 

– undergo a ten-fingerprint scanning process, which is conducted by a customs agent. This 

scan is only performed upon entry into the United States. DHS is investigating the feasibility 

of deploying an unassisted “self-service” fingerprint scanning solution as well for when 

foreign nationals exit the country.

To that end, DHS requested assistance from NIST to examine the affordances of the

fingerprint scanner when used with the US-VISIT instructional poster, both of which were in 

use at U.S. ports of entry when this study was conducted (Feb-Mar 2010), to learn how 

travelers interpret these features. For example, whether they help travelers use the scanner in 

such a way that the scanner can capture clear pictures of travelers’ prints, and whether a 

person can present a usable fingerprint sample to the scanner without assistance. Findings 

from this study will inform future efforts to design a self-service fingerprint solution that can 

be effectively used by the vast majority of people regardless of age, nationality, or level of 

technical proficiency.

In this study, 62 participants used the same instructional poster and fingerprint scanner 

employed by the US-VISIT program and underwent the same process employed in that 

program, except that they did not receive any guidance from the person operating the 

fingerprint scanner. We observed their behavior during the process, evaluated how well they 

completed the fingerprinting task, i.e., whether they got the scanner to take a clear picture of 

some or all of their fingerprints, and afterwards we asked them questions about their 

experience using the scanner.

Our findings indicate that the US-VISIT poster and scanner, as implemented, will not 

constitute a workable self-service fingerprinting solution. The US-VISIT poster provided our 

study participants with a general idea of what to do, but left them unsure of specifics such as 

how long to hold their fingers on the platen or how to tell whether the scanner had managed 

to get a clear image of their fingerprints – a finding consistent with a previous study 

involving a similar instructional poster [11]. The affordances on the scanner itself, consisting 

of instructional icons and light emitting diodes (LEDs), are designed to provide this 

information; however, many participants either failed to notice or misinterpreted them.

Users will need additional support in the form of more detailed instructional material, 

feedback from the scanner, or both. Any self-service solution needs to clearly communicate 
NISTIR 7944 Page 2 9/2013

what is expected of the user and indicate whether the user is or is not meeting those 

expectations.

1 INTRODUCTION

The National Institute of Standards and Technology (NIST) has conducted a series of studies 

focusing on the usability and human factors elements that affect the capture of fingerprint 

and facial images for the United States Visitor and Immigrant Status Indicator Technology

(US-VISIT) program. In one study, NIST evaluated the effectiveness of a face overlay guide 

in helping operators center subjects’ faces when capturing a facial image [7]. A subsequent

study examined how instructional materials could be used to guide travelers through a 10-

print collection process [11]. These tests were funded by DHS.

Both studies examined the effectiveness of affordances in or on the devices being tested. An 

affordance, as originally defined by J.J. Gibson in the late 1970s, refers to the "actionable 

properties between the world and an actor (a person or animal)." As Donald Norman points 

out, in design, "What the designer cares about is whether the user perceives that some action 

is possible" (emphasis added) [3]. We would add that the user must perceive that the action 

we want them to take is possible and desirable as a step in reaching a goal. The results of the 

NIST studies indicated that there is still work to be done to identify characteristics that 

improve affordances and, in turn, the performance of travelers during biometric data 

collection processes.

A key part of the US-VISIT apparatus is the fingerprint scanner. Studies show that women 

and older adults typically need many more tries than younger males do to use the fingerprint 

scanner to obtain usable images of their prints [8]. In the current setup, which is only for 

entering the country, a Customs and Border Protection officer guides travelers through this 

process. Work performed prior to the study suggested that many people would not be able to 

use the scanner successfully without assistance. NIST’s prior research in this area found that, 

while instructional materials helped people in the study to provide clear, usable fingerprints, 

the form of the instructional materials affected the process [11]. 

This study examined the light emitting diode (LED) indicators and instructional icons on the 

fingerprint scanner type1 in place in U.S. ports of entry (at the time of the study) to learn if

 

1 The use of certain commercial equipment in this study is not intended to imply recommendation or 

endorsement by National Institute of Standards and Technology, nor is it intended to imply that the 

equipment shown is necessarily the best available for the purpose.
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people interpret these features as intended, are guided through the fingerprint collection 

process, and whether they can present usable fingerprint samples to the scanner without 

assistance. The results from this study will be used to inform the development of a “selfservice” fingerprinting solution.

2 OVERVIEW AND BACKGROUND

The study described in this report investigated whether users can accomplish the following 

without assistance: 1) determine the order and positioning of hands and fingers on the 

fingerprint scanner's platen by looking at the lights on the scanner and using the instructional 

diagrams in the US-VISIT poster, and 2) by doing so, produce quality fingerprint images. 

The results and recommendations from this study will inform decisions feeding into the 

design of a US-VISIT “self-service” fingerprint scanning device.

2.1 FINGERPRINTING TERMINOLOGY

In this study, we frequently use the following terms associated with the fingerprint scanning 

process: [5]

• User – This is the person whose fingerprints are being scanned, rather than the 

system operator. The participants in this study are users.

• Presentation – The display of biometric characteristics to a sensor. In this case, a 

user presents his/her fingerprints by placing his/her finger(s) on the platen of a 

scanner.

• Capture – The collection of data on biometric characteristics presented by a user. In 

this case, a fingerprint scanner captures a digital image of a user’s fingerprint(s). 

• Slap – The specific term for presentation of fingers to the fingerprint scanner. The 

US-VISIT fingerprint collection involves a sequence of four slaps: the four fingers of 

the right hand, without thumb (right four-finger slap); the right thumb; the four 

fingers of the left hand (left four-finger slap); and the left thumb.

For purposes of this study, a successful presentation means a slap from which the fingerprint 

scanning system was able to capture an image. Typically, an unsuccessful presentation means 

one of the following: 1) the system was unable to capture anything, 2) an incomplete set of 

fingers (relative to what was presented) was captured for a right or left finger slap, or 3) a

finger or slap was captured that differed from the slap expected by the scanner. Additionally, 

for the purposes of this study, our procedure was to accept any print the scanner attempted to 
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collect, regardless of order. An incomplete set of successful presentations is another type of 

failure.

2.2 USABILITY METRICS

A self-service fingerprint scanner must possess a critical general property: usability. The 

definition of usability, according to ISO 9241-11, [1] is "the extent to which a product can be 

used by specified user to achieve specified goals with effectiveness, efficiency and 

satisfaction in a specified context of use." The assumption inherent in this definition is that 

the measures are applied in an evaluation of a finished design.

In the case of this study, however, the measures were applied in an exploratory fashion to 

examine the behavior and perceptions of users. Because this study was exploratory, we 

employed different metrics from those used for summative tests. We wanted to learn whether 

people noticed the affordances on the fingerprint scanner, e.g., lights, icons and audible tones 

as identified in Section 3.2, and if they did, whether they understood the affordances, and if 

the affordances helped them present their fingerprints in such a way that the scanner was able 

to successfully capture images of acceptable quality, i.e., a NIST Fingerprint Quality [NFIQ] 

score of 1 – 3, indicating the quality assessment to be a level that is an excellent (1) to good 

(3) predictor of a fingerprint matcher’s performance [6].

Again, due to the exploratory nature of the study, efficiency metrics were not part of the 

scope of this study. For example, though we were aware of the time it took participants to 

scan their fingerprints, we did not measure performance against time on the task. At this 

early stage, we were more interested in whether people were able to use the scanner 

successfully while unassisted – whether they were effective in providing fingerprint images at 

all, and whether those prints were of sufficient quality.

Additionally, we were interested in the study participants’ perceptions of the scanner and the 

process of using it. We wanted to know whether participants were confident in their ability to 

use the scanner to capture prints without assistance and to compare participants' confidence 

levels with their success in capturing usable prints. We were also interested in knowing their 

impressions of what guided them through the process and the clarity of that guidance rather 

than their overall user satisfaction. 

If participants were both confident and successful in providing usable fingerprint samples, 

the design of this scanner could be considered viable for a self-service fingerprint capture 

device. If participants were successful but not confident, we would be able to make 

inferences about what users would need to perceive progress and completion. If participants 

were not successful but were confident, this might indicate serious flaws with the scanner’s 
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affordances; and, we would gain insights on how to set appropriate expectations in the design 

of the self-service device.

3 METHOD

In this study, we focused on users undergoing an unassisted fingerprint capture process using 

the fingerprint scanner type in use at U.S. ports of entry. In the test scenario, users had some 

written instruction via the US-VISIT poster, shown in Figure 1, page 6, on how to go through 

the process, but no human assistance. Our objectives were twofold: first, we wanted to 

investigate the perceptions of users undergoing the process, and second, we wanted to assess

participants’ effectiveness in the test scenario.

3.1 MATERIALS

The materials used by participants and researchers in the study are listed below.

3.1.1 Materials for participant use

• Fingerprint scanner

• Informed consent form explaining the study and how the data would be used

• Demographic questionnaire asking about ethnicity, occupation, handedness, and 

experience with biometric data collection, contained in Appendix A: User 

Demographic Survey

• 45.7 cm by 58.4 cm (18 in x 23 in) US-VISIT poster displayed on the wall in front of 

the participant with basic instructions describing how to present fingerprints for 

capture, depicted in Figure 1
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Figure 1: Instructional US-VISIT poster providing the biometric data capture process

• Unlabeled diagram of the fingerprint scanner used by the participant to draw any 

features they noticed on the device, as shown in Figure 2. The diagram of scanner 

that participants annotated measured approximately 16.0 cm by 15.2 cm, whereas the 

scanner measured 15.2 cm by 15.2 cm. 
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Figure 2: Diagram of scanner that participants annotated

• Post-task questionnaire that asked participants questions about their experience with 

the fingerprint scanner, including how confident they were that they had used it 

correctly, how clear and effective they considered the US-VISIT poster and scanner 

affordances to be, and whether they had any additional comments on the 

fingerprinting process. The questionnaire is provided in Appendix C: Post-Task 

Survey.

3.1.2 Materials for researcher use

• Script containing directions on what to say to participants, how to move from station 

to station in the lab space, and how to collect data

• Data collection sheets for recording observations and participants’ comments, 

provided in Appendix B: Fingerprint Scanner Datasheet

• Vendor-supplied image capture and management software

3.2 EQUIPMENT

The fingerprint scanner used in this study – shown in Figure 3 – measured approximately 

15.2 cm (6.0 in) by 15.2 cm (6.0 in) by 15.2 cm (6.0 in). There were four LED lights at the 
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top edge of the scanner platen surface, each capable of emitting a red or a green light. On 

each side of the platen were two illuminated indicators (four in total) corresponding to a 

Right Slap, Right Thumb (on the right side), Left Slap, and Left Thumb (on the left side). 

The scanner also emitted audible tones – beeps – whenever it successfully captured a print 

image. Note that what appears to be a horizontal line or delineation between the left and right 

icons is inside the scanner and not anything present at the surface of the platen.

Figure 3: Fingerprint scanner with indicators

To control the fingerprint scanner and collect the digital images of participants’ fingerprints, 

the image capture and management software supplied by the scanner vendor was used.

Figure 4 contains an image of the operator’s view of an example of a slap image captured 

using this software. Figure 5 provides an example of a complete set of captured fingerprints –

the ideal outcome of the fingerprinting task. 

LEDs glowed red at the 

beginning of the process and 

when the participant’s finger 

position was incorrect; they 

glowed green when finger 

positioning was correct

Icons indicating the type and 

sequence of each slap for the 

user to perform
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Figure 4: Screen image showing positioning of a right slap on the platen

Figure 5: Screen image showing a complete set of prints as captured and stored
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3.3 PROCEDURE

After filling out a demographic questionnaire, each participant went through a two-part 

process. First, the participant used a fingerprint scanner while being observed by, but 

receiving no assistance from, the researcher. The researcher also operated the fingerprint 

scanning software, which required only occasional glances at a computer monitor and 

clicking of the mouse. Second, the participant was asked to provide feedback on his or her 

experience with the scanner and any related thoughts or impressions. Each of the two parts 

took roughly 8 to12 min, depending on the participant. As part of the analysis after data 

collection was completed, the quality of the captured fingerprint images was assessed with 

the NFIQ algorithm.

3.3.1 Part 1: Scanning fingerprints

The researcher explained to each participant that foreign nationals use the fingerprint scanner 

at major U.S. airports. In addition, the researcher asked participants to verbalize while using 

the scanner, specifically to talk about what they were doing and their observations during the 

process.

The researcher did not provide the participants with any assistance or instructions on how to 

complete the task before or during the process. The only guidance the participants received 

came from the US-VISIT poster on the wall in front of them and the affordances of the 

fingerprint scanner itself.

While the participant underwent the scanning process, the researcher took notes on the 

participant’s behavior, recorded any comments the participant made, and responded to 

occasional prompts from the scanner’s operator interface (see Section 3.3.1.3).

3.3.1.1 The scanning process

As shown in Figure 3, the fingerprint scanner had 4 LED lights across the top and 4 slap 

icons along the sides of the platen. When the scanner was ready, all of the LED lights were

red and one of the four indicators on the sides of the platen was illuminated. The sequence in 

which the indicators were illuminated corresponded to the US-VISIT slap sequence: right 

four-finger slap, right thumb slap, left four-finger slap, and left thumb slap.

Once the participant placed a thumb or fingers on the platen, the four LED lights indicated 

whether or not the scanner was able to read the user’s fingerprints for the particular slap. 

When the user performed a right four-finger slap, the corresponding LED lights, e.g., the one 

on the far left for the index finger, the one on the far right for the little finger, turned from red 
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to green if the scanner was able to read the appropriate fingerprints. Once all four lights 

turned green – indicating that all the fingers were readable – the scanner checked the quality

of the fingerprint image it was attempting to capture. After a few seconds (presumably 

checking the quality), if the quality was acceptable, the scanner captured the image and

beeped, indicating that it successfully captured an image. If the quality was insufficient, the 

scanner would stay on the same slap, until a successful capture or the scanner timed out and 

moved to the next slap. The process was similar for a thumb slap, except that the only LED 

illuminated was either the second one from the right (for a right thumb slap) or the second 

one from the left (for a left thumb slap).

3.3.1.2 Fingerprint capture software

While the fingerprint scanner scanned participants’ fingerprints, the LSMS software running 

on an attached PC displayed the fingerprint images to the researcher. The software rated the 

image quality using a proprietary measure. Note, that this assessment was employed by the 

scanner software to set a quality threshold to be met before an image was stored. In the 

system configuration used in this study, the software would automatically store fingerprint 

images only if they had a quality score of 3 or better. This quality assessment was different 

than the use of the NFIQ score for prints that were captured – a metric used to analyze

whether the captured fingerprint images were of “good” or better quality after the data 

gathering portion of the study had concluded (described in 3.3.3). 

However, if there were other issues that affected fingerprint image capture – for example, if 

there appeared to be digits missing from a slap – the system would display a message prompt 

on the operator’s monitor, asking whether it should accept or decline the captured image.

These were accepted. Similarly, it was not unusual for slaps to be captured in the wrong 

order because the first good image was often the right thumb. When the LSMS software 

detected this, it showed the scanner operator the “accept/decline” message described above.

The researcher operating the scanner in this study always chose to “accept” the image. 

Note: after the data were collected, we found that in cases where the researcher directed the 

software to accept a right or left 4-finger slap while the scanner was looking for a thumb, 

produced a situation where the scanner indicated to the participant that the print had been 

captured (beep given) however, the software did not store the image. There were six 

participants who experienced this. Since these participants did not have any other successful 

prints and these out-of-order prints were not captured, these participants were categorized as 

having no fingerprints collected, even though they received the beep.
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3.3.1.3 Researcher activity during scanning process

The object of the study design was to simulate as much as possible a scenario in which a user 

undergoes an automated fingerprint scanning process without any kind of assistance. 

Therefore, whenever the LSMS software prompted the researcher to accept or decline 

captured images from a participant’s slap, the researcher’s default decision was to accept. If 

there was no capture but the system showed an accept/decline prompt, the scanner operator

simply did whatever he/she needed to do to allow the test to move forward. This meant that 

slaps for some participants were stored in the wrong order, e.g., a right thumb slap when 

there should have been a right four-fingered slap.

In some cases, a participant would attempt a slap multiple times. In this study, we define an 

"attempt" or "try" as placing the finger(s) on the platen. So, if a participant lifted his/her 

fingers to change their position on the platen, the researcher counted that as an attempt, and 

recorded the number of attempts participants made for each slap.

3.3.2 Part 2: Collecting participant feedback

After the participant completed the fingerprint scanning process, the researcher gave him/her 

a black-and-white line drawing of the surface of the scanner Figure 2. The diagram showed 

the basic outlined shapes, without color or detail, of the LED lights and slap icons at the 

edges of the scanner platen. The researcher instructed the participant to draw and label on the 

diagram any features the participants recalled from the scanner during the fingerprinting 

process, including what the scanner did. The participants did not have access to the actual 

scanner or instructional poster during this exercise. Participants often described what they 

were drawing or writing without prompting from the researcher. 

When the participant said he/she was finished drawing on the diagram, the researcher asked 

the participant to describe what he/she remembered seeing during the scanning process. If the 

participant did not mention the lights, slap icons, and beeps in his/her description, the 

researcher asked the participant if he/she remembered them.

Finally, participants completed a post-task questionnaire that asked them about various 

aspects of their experience with the scanner, such as whether they thought the US-VISIT 

poster provided them with helpful instructions on how to use the scanner, whether the lights 

on the scanner itself were useful indicators, and how confident participants were that they 

had used the scanner correctly. Appendix C: Post-Task Survey contains the entire 

questionnaire.
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3.3.3 Post-processing of the collected images

After the data collection phase was complete, assessment of the print quality was performed 

in the following manner: for the prints that were captured, the NFIQ value was computed as 

an assessment of quality. The NFIQ scores were obtained for individual prints by taking each 

image stored by the scanner for each participant, which was a digital image of a set of 

fingerprints, arranged similarly to that of an inked fingerprint card. That image was 

segmented into a set of individual images, one for each fingerprint captured. Images of 

individual prints were assessed with the NFIQ algorithm [6], using the NIST software that 

implements the NFIQ algorithm [3]. 

3.4 PARTICIPANTS

A total of 62 participants used the fingerprint scanner in this study. 30 were men and 32 were 

women. The average age was 38 years, with participants ranging in age from 20 to 66 years.

We measured the height of each participant to counterbalance two heights for the fingerprint 

scanner. The shortest participant was 152.4 cm (60 in) in height, the tallest was 195.6 cm (77

in) tall, and the mean + standard deviation = 175.0 cm + 9.6 (68.9 in + 3.7). The table height 

of the scanner was either 91.4 cm (36 in) or 106.7 cm (42 in) for each participant: the former 

is a recommended height based on the findings of an earlier fingerprint capture usability 

study [9], and the latter is the most common height used with fingerprint scanners at USVISIT stations [10]. Subjects were assigned to a table height in a counterbalanced fashion.

Thirty people used the scanner at the lower (91.4 cm) table height; 32 people used the 

scanner at the higher (106.7 cm) height.

3.5 RESEARCH QUESTIONS

In this study we addressed the following questions:

• Did participants notice the slap icons and LED indicators on the scanner?

• Did the slap icons and LED indicators on the scanner help participants successfully 

capture their fingerprints?

• Did the US-VISIT poster help participants succeed in presenting their fingerprints in 

such a way that the system could capture quality images of them?

• How confident were participants that they used the scanner correctly?

• Secondary question: Would table height, on which the scanner rested, have any effect 

on performance in this study?
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4 RESULTS

In this section we present the qualitative and quantitative data resulting from the study.

Subjects were asked to relate, “your impressions of what is happening as you use the 

device,” as they worked through the task of presenting and having their fingerprints scanned. 

The observer recorded comments made by participants as they used the scanner and 

immediately following use. We present representative comments intermingled with the 

quantitative findings in an effort to let the data and participants relate the experience of using 

the scanner during this study.

4.1 COMPLETING THE TASK

4.1.1 Overall print capture success

Successful presentations were more the exception than the rule: the overall capture rate for 

participants’ prints was very low. As shown in Table 1, only 10 of the 62 participants 

captured a full set of prints, 9 captured some but not all prints, and the remaining 43 

participants failed to capture any prints at all.

Table 1: Overall fingerprint capture success rate

Captured... Full set of 

prints

Some, but not 

all prints

No prints Total

Number of 

participants

10 9 43 62

Percentage of 

participants

16.1 % 14.5 % 69.4 % 100 %

Often participants did not know if they had successfully left prints or not, or could not 

ascertain if they had completed the task of having their fingerprints scanned. The following 

quotes from participants illustrate this issue:

• “Confusing... No feedback... if it had captured the images. No feedback to begin or end.” 

[s1]

• “Did it work?” [s2]

• “Don't know when to stop or when to lift.” “Don't know when it's done or when to lift.” [s6]

• “Supposed to tell me when I should go to the next one?” [s7]

• “It was happenstance, chance that anything was captured.” [s9]
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• “Do you just assume that it worked and go on?” [s12]

• “It doesn't beep or anything so am I just to assume it's working?” “I don't know if the process 

is completed or not.” [s13]

• “How do I know when to go to the next one? Doesn't tell me when to go to the next one. Not 

user friendly at all. Hope they don't use this machine. They'll have people lined up all over the 

place. There are no instructions. It's not working.” [s34]

Participants who successfully left a full set of prints also made observations about the 

process that included the following:

• “I was confused at first, but then I saw the green and red lights come on.” [s38]

• “Don't know when to take my fingers off. All red. Red means no. Ok. Try again. Ok. You have 

to fit your fingers in where these little dashes are. Now all green.” “That's the ticket.” [s60]

4.1.2 The capture process - researcher observations

The researcher responsible for observing participants noted that when participants first 

presented their fingers for a scan, they would often carefully touch the platen, look up at the 

US-VISIT instructional poster, and then possibly note the LED lights on the scanner 

changing color from red to green.

Many participants placed at least one finger on the top half of the platen outside of the 

scanning area, did not press their fingers down on the platen hard enough to capture a clear 

image, and/or shifted their fingers around on the platen while the scanner was trying to detect 

them. Most participants, seeing that only some of the LED lights turned green, either 

assumed that the LED lights were scan progress indicators or that the LED lights were 

showing them that their slap had been captured.

Even if they correctly interpreted the LED lights as indicators that their fingers were properly 

positioned, participants often thought the scanner would capture their fingerprints more 

rapidly than it actually did. Even though participants reported that they expected to hear a 

beep upon successful capture, many participants lifted their fingers from the platen before the 

system actually processed the scan, and thought that the scanner had successfully captured 

images of their fingerprints when, in fact, it had not.

Also, if the scanner could not capture the expected slap image, it would continue until it 

either successfully captured a fingerprint image or moved on to the next slap in the sequence. 

Participants who mistook a successful capture for an unsuccessful capture would often move 

on to the next slap in the sequence before the scanner did, e.g., they would move from a right 

four-finger slap to a right thumb slap when the scanner was still trying to “find” the right 

four-finger slap. In such cases, the best possible outcome was a partial set of captured 
NISTIR 7944 Page 16 9/2013

fingerprint images – and those images would be out of order, e.g., the scanner software 

would end up storing a right thumbprint for a right four-finger slap.

4.2 NOTICING AND INTERPRETING THE AFFORDANCES

Participants had the following potentially instructive indicators, as well as the US-VIST 

poster, on which to reply for guidance through the scanning process:

• Slap icons on the sides of the scanner platen

• LED lights above the scanner platen

• Beeps emitted by the scanner upon successful image capture

The researcher captured quotes both during the fingerprint capture process and while 

participants were discussing the diagram they had labeled. Excerpts from what participants 

related to the researcher and wrote during the post-task survey are provided in the following 

sections. Note that even through the researcher did not respond to comments that were posed 

as questions, some participants persisted in phrasing their comments in question form.

4.2.1 During the capture process

Not all participants spoke aloud during the fingerprint capture process, but for those who did, 

their comments were categorized according to the topic area whether that was an affordance 

or something else, for example, an illustration of general understanding. The remaining 

comments were grouped as Miscellaneous. The quotes provided here are representative of 

the comments provided, but it is not an exhaustive list, as numerous instances referring to a 

common theme were omitted. Some items contain [bracketed contextual information] to

supplement the quote; direct quotes are always contained within quotation marks. A brief 

summary is provided for each category or subcategory.

Slap Icons

Comments on the slap icons fell into three groups: reflection on usability issues made by s5 

and s43, noticing that an icon was lit but unchanging (s14 and s48), and finally the thought 

that these slap icons were active buttons (s25 and s38).

• “Should be brighter.” [s5]

• “I see this is lit up, but it doesn't change.” [s14]

• “Tap them?” [Pressed each one in turn.] [s25]

• “Do I have to press anything?” [s38]
NISTIR 7944 Page 17 9/2013

• “The graphics aren't clear. The thumb looks like it's pushing a card.” [s43]

• “I see this is lit up. But it's not changing.” [s48]

LED Lights

Participants had difficulty discerning the exact meaning of the LED lights. When they 

noticed them turning green, often they expressed that they thought this was a verification of 

some sort, although at times participants did not know what it meant at all. Unfortunately, a 

notion repeated by a number of participants was that a green light meant the print had been 

captured.

• “Should I leave them here? Or wait until they all turn green?” [s3]

• “Maybe the light’ll go out. Now one of the lights is green, but I don't know if it's captured it. 

Frustrating.” [s5]

• “Don't have a clue what to do next.”“Confused by flashing lights.” [s6]

• “They weren’t all lighting up in the same way as on the others, so I took it upon myself to lift 

off.” [s9]

• “Assuming it's a verification -- that green light.” [s10]

• “Now I'm just playing around. I notice that the signal area [red/green lights] changes color as 

it captures.” [s11]

• “Green light - does that mean it's not all there? Seriously?!” [s18]

• “What do the 4 lights mean?” [s21]

• “Green means it captured that finger.” [s44]

• “Some have changed to green, but I don't know why.” [s56]

Beep

The participant comments illustrate that not all participants received a beep and they 

expected some sort of confirmation that a print had been captured. S5’s comment also 

illustrates that he did not know how to tell which slap was expected by the scanner.

• “Does it automatically scroll to the next one? If it beeped?” [s5]

• [After receiving a beep] “Yes!” [s43]

• “I haven't heard a beep. Am I doing it wrong?” [s61]

• “I would hope it would make noise to tell me if I did it the right way.” [s62]

Poster

Regarding the poster, participants wanted more information about the process, and 

specifically requested was information regarding the lights and timing of the capture process. 

Additionally, one participant noted confusion that the platen depiction on the slap indicators 
NISTIR 7944 Page 18 9/2013

was not consistent with the scanner in front of him, while another participant felt the poster 

was not particularly readable.

• “Wasn't very readable.” [s1]

• “Confused. On the poster the dark part is on the bottom, but on the device it's on the top.”

[s8]

• “Would have been nice to have more about the lights, but I get that you're dealing with the 

language component here.” [s24]

• “Should have just about how long to leave fingers on.” [s25]

Scanning Area

When participants made comments regarding the scanning area, it usually reflected their 

uncertainty about where to position their fingers on the platen.

• “Am I supposed to get my fingers within the black lines?” [s4]

• “Whether to use the whole area or just part?” [s20]

• “I like the rubber feeling to it, but might be better to be able to lay your fingers down.” [s28]

• “Does it need to be in where the little dots are? Or the whole thing?” [s59]

• “I don’t know where to press. In the area that's light green?” [s62]

Overall Understanding

Comments in this category reflect participants general (lack of) understanding especially 

regarding if and when they had completed a capture and when it was time to move on. 

Additionally, some comments reflect participants’ thoughts about finger placement and the 

lack of feedback if they had placed their fingers on the platen properly for capture. 

• “I don't see any indication ... that anything has happened. I don't like the fact that it's not 

telling me anything.” [s14]

• “When do I go on to the next one? Will know when to switch?” [On tip toes] “There's no light 

turning on.” “Nothing indicating that it took. Would expect all 4 to turn green to show it 

scanned successfully.” “There's no sound in any of them. Not seeing anything [more] to show 

it is doing anything.” [s15]

• “Am I done? It doesn't... Okay, now I feel like an idiot. I'm so confused. Obviously, I'm not 

doing this right because the light on the right is still on.” [s17]

• “Should I hear something when it's done? The two end lights are green. I should think there 

should be some type of sound. Maybe it's telling me... No idea if it recorded the first four. I 

have no idea what's going on.” [s22]

• “Do I line 'em up with the dots? Do I pull them off? Ok. I'm just going to follow the procedure.”

[Points to the poster.] [s23]
NISTIR 7944 Page 19 9/2013

• “Nothing's happening. I saw the lights flash. Waiting for something to happen. Don't know if 

it's going to tell me to go to the next step. Not sure how long to stay here. Figure it would 

beep or lights would flash.” [s25]

• “Would like for it to tell me when I'm done.” [s28]

• “One green light. Is it gonna beep or anything when it's done? How long do I leave it there? 

Green light flashed. How long should I leave it here?... Oh! It beeped. Does that mean I take 

it off? Fourth green came on - Just thinking you wouldn't need to leave it on that long.” [s30]

• “Should I take my hand off? It's like alien technology. The thumb light [icon] isn't on.” [Moves 

on.] “Should I take my hand off?” [s31]

• “I guess just putting fingers... don't know when it's complete.” [Had to turn her body to reach 

for the thumb.] “Oh, I see, when they all light up red, it means they're good to go... Maybe 

not. I wasn't sure... I think it's the green that makes it accepted.” [s33]

• “How do I know when to go to the next one? Doesn't tell me when to go to the next one. Not 

user friendly at all. Hope they don't use this machine. They'll have people lined up all over the 

place. There are no instructions. It's not working. I feel real dumb right now.” [s34]

• “Am I just supposed to follow the steps [on the poster]? When do I change fingers?” [s35]

• “No idea how long to leave my fingers on here. I see lights, but I have no idea if it's recording 

anything.” [s36]

• “Oh, green lights. Which don't tell me anything. They're gone. Beep. No beep? Still nothing. 

One green light. And beep.” [s37]

• “Not sure how long to keep it on there. Just a second, or...? It should have some sort of beep 

or something. Not sure what the green light is indicating as opposed to the 3 red ones. It 

needs some sort of feedback.” [s40]

• “If the green is on, it read it? ... Did I get it? I don't know. I don't think so, cuz a green light 

came on but not all. I'll try again.” [s42]

• “Should fingers be close or spread? I'm thinking how hard I should press. And how long?”

[s53]

• “Doesn't tell me how long or hard or beep. Doesn't give me any guidance. How far up or back 

to put my fingers.” [s56]

• “Don't know when to take my fingers off. All red. Red means no. Ok. Try again. Ok. You have 

to fit your fingers in where these little dashes are. Now all green.” ... “That's the ticket.” [s60]

Miscellaneous

Some of the comments in the Miscellaneous category were impressions of physical aspects 

of the device; while other comments reflected an emotional response produced by use of the 

device.

• “Green light is scary” [s1]

• “If I was running late for my plane this would tick me off.” [s44]
NISTIR 7944 Page 20 9/2013

• “Step 1 seems pretty obvious... I kind of expected it to beep when I'm done, but based on the 

lights... I'm waiting for them all to show up green. Can't get [my pinky] to stay green. Don't 

know if...” [s45]

• “The shape is awkward. The box is clunky.” [s49]

• “My first time when I used it, I was scared, I asked my mother why they're doing this.” [s57]

4.2.2 Diagram labeling

After completing the fingerprinting process, participants drew on the diagram shown in 

Figure 2. One example is shown in Figure 6.

Figure 6: An example of a participant’s scanner diagram where most features are labeled correctly
NISTIR 7944 Page 21 9/2013

The example above is very detailed and almost completely correct. The slap icons along the 

sides of the platen are correctly labeled and the participant clearly understood their purpose 

(“each step lights up so you know what to do”). The participant also correctly labeled the 

LED lights above the platen, however the interpretation of the function was incorrect – green 

light(s) indicate positioning is suitable for scanning, not that the fingerprint was “properly 

scanned”. In this case, the participant also outlined the scanning and non-scanning areas of 

the platen.

However, most participants did not label this many features correctly, if at all, in their 

scanner diagrams, such as the one in Figure 7 below.

Figure 7: An example of a participant's scanner diagram where only some features are labeled correctly
NISTIR 7944 Page 22 9/2013

Notice that while this participant correctly labeled the slap icons, he/she did not seem to 

understand the purpose of the LED lights above the scanner platen. In fact, the participant’s 

diagram indicates that he/she may have misremembered where the LED lights were actually 

located on the scanner. Some participants did not label the LED lights on their diagrams at 

all. 

The diagram shown in Figure 8 is from a participant who did not capture any prints. This 

particular participant did notice the LED lights but did not understand their function. They 

did not notice the slap icons or experience the beep.

Once participants had completed labeling the diagram of what they remembered of the 

scanner, the researcher determined for each affordance if 1) it was noted at all, 2) its function 

Figure 8: An example of a participant's scanner diagram with minimal labeling
NISTIR 7944 Page 23 9/2013

was described, and 3) its function was described correctly. Table 2 provides the counts of 

how participants labeled the diagrams according to how they fared in capturing prints.

Table 2: Diagram labeling summary

Affordance Condition

Prints captured

All

n=10

Some

n=9

None

n=43

Slap icons

Notice Icons 9

(90.0 %)

2

(22.2 %)

25

(58.1 %)

Provide labeling for 

Icons

9

(90.0 %)

2

(22.2 %)

23

(53.5 %)

Correct labeling for 

Icons

9

(90.0 %)

2

(22.2 %)

7

(16.3 %)

LED lights

Noted LEDs 10

(100.0 %)

9

(100.0 %)

38

(88.4 %)

Provide labeling for 

LEDs

10

(100.0 %)

9

(100.0 %)

37

(86.0 %)

Correct labeling for 

LEDs

7

(70.0 %)

2

(22.2 %)

4

(9.3 %)

Beep

Notice beep 10

(100.0 %)

8

(88.9 %)

9

(20.9 %)

Provide description of 

beep

10

(100.0 %)

8

(88.9 %)

8

(18.6 %)

Correct description of 

beep

10

(100.0 %)

6

(66.7 %)

4

(9.3 %)

The data reflect that participants who captured all prints noticed and correctly interpreted the 

slap icons, LED lights, and beeps for the most part, although the number of participants who 

correctly interpreted the LED lights was lower than for the other affordances. The one person 

who did not notice the slap icons presumably followed the US-VISIT poster for the slap 

order.
NISTIR 7944 Page 24 9/2013

For the group of nine participants who captured some prints, relatively few noticed and 

correctly interpreted the slap icons (two of nine). However, all of them noticed and had some 

theory regarding the function of the LED lights, however relatively few correctly interpreted 

the LED lights (two of nine). Most of this set of nine noticed and had a theory as to the 

function of the beep (eight of nine), although six of nine correctly interpreted the meaning of 

the beep.

For the group of participants who did not capture any prints (n=43), 25 noticed the slap 

icons, while 23 had a theory as to their function, although only seven (16.3 %) correctly 

interpreted the meaning of the slap icons. 38 of 43 noticed the LED lights, although only four

(9.3 %) participants actually correctly interpreted their meaning. Finally, regarding the beeps: 

six participants in this group actually received a beep at least once during their interaction 

with the scanner. Five of those six recall noticing the beep, while an additional four 

participants reported hearing a beep, even though they never received one (note that many 

participants reported expecting to hear a confirmation of capture), for a total of nine 

reporting hearing a beep. Four of the six who did receive a beep, correctly interpreted its 

meaning, even though the system did not ultimately store the image capture it had confirmed.

During the process of the researcher and the participant working through the labeling 

provided by the participant on the diagram, the researcher recorded comments made by the 

participant. A list of comments is provided here, which is not exhaustive, but is 

representative of the comments given by participants during this phase of the debriefing. 

Again, comments are grouped by topic with a short summary for each topic.

Slap Icons

While a few participants correctly interpreted the meaning of the icons, others did not. Some 

participants thought the slap icons were active buttons to be pushed. Some participants either 

had an incorrect interpretation slap icons or had no idea and were just confused by them. One 

participant commented that the symbol did not look like what it was supposed to represent –

a thumb.

Correct interpretation

• “Reminder of what you had to do. Guide you.” [s18]

• “Which fingers to press.” [s31]

• “Lit to guide additionally to say which set to place on the glass.” [s45]

• “Showing me which fingers to put on the scanner, step by step.” [s57]

Incorrect interpretation

• “Didn't notice the lights changing at all. Wasn't clear if these need to be pressed. Assumed 

when it lights up, the image was taken. Not too clear.” [s14]
NISTIR 7944 Page 25 9/2013

• “Didn't know how to change to proceed.” [s15] [Thought she needed to push it.]

Other observations

• “Originally thought that's where we start, but the light didn't go off, then one of these went 

green and the [icon] stayed lit. Pretty confusing.” [s5]

• “I thought the light meant something, but I don't know if it did.” [s25]

• [Symbol] “Doesn't look like a thumb, though.” [s43]

• “Didn't really look at those.” [s48]

• “Wasn't sure if these were buttons.” [s51]

• “I don't think they meant anything.” [s52]

• “Do I press them? To allow me to go on. At the time, I had no clue.” [s55]

LED Lights

Some participants correctly interpreted the meaning of the LED lights, as reflected in some 

comments. Other participants did not interpret the exact meaning of the lights changing to 

green – they gathered that green meant proper positioning but then assigned additional 

meaning incorrectly, i.e., that green LED lights meant the fingerprint had been captured. Still 

others found them completely confusing or at best inconsistent.

Correct interpretation

• “There were red lights that didn't change. It was probably telling me that I wasn't doing it 

correctly. And there were no instructions about what to do.” [s36]

Incorrect interpretation

• “No information given about them. Had to observe them change." "Indicators as to where to 

put them and after they turn green they've captured the image.” [s3]

• "Completely confusing. Supposed to tell you when you were finished, but it made no sense to 

me.” [s5]

• “I don't know. Green is go, red is stop, but it was intermittent what that meant when some 

were green and some were red.” [s15]

• “Thought they were going to turn the same color when you were done. I assumed stop and 

wait for prints to be taken. Then green to go.” [s17]

• “When a finger was processed, it turned green.” [s21]

• “It didn’t tell me anything. Though green would tell me it had taken the picture.” [s25]

• “We were recorded. The lights were red.” [s29]

Other observations

• “Didn't really catch if that was related to my fingers on the screen. Wasn't real clear about 

when I might have started and stopped that.” [s2]

• “I don't know if they have to be all green at the same time.” [s4]
NISTIR 7944 Page 26 9/2013

• “I remember the lights flashing, but I don't know what they were for.” [s7]

• “Not sure. Didn't seem consistent.” [s9]

• “Finger light indicators, telling you whether your finger was readable. If it wasn't readable, it 

was a red light.” [s16]

• “When I put my hand on, it turned green.” [Telling you?] “Nothing.” [s31]

• “That it was done or that my fingers were pressing too hard or not hard enough.” [s61]

Beep

Some participants did not recall hearing a beep, and in fact, they did not receive a beep, as 

they left no prints. Other participants correctly interpreted the beep to mean the fingerprint 

had been captured and they could lift their fingers and move on. Still others thought the beep 

was associated with a camera: one said it was a camera taking a picture of the fingerprint and 

the other participant said they thought their picture was being taken.

Correct interpretation

• “Completed with the step, move on.” [s10]

• “Indicate the grouping had been successfully read.” [s16]

Incorrect interpretation

• “You're finished, you can lift your hand up. You're done.” [s18]

Other observations

• “I remember not hearing any sounds.” [s14]

• “Camera taking the picture of the fingerprint.” [It] “clicked like a camera.” [s27]

• “I don't associate them with anything that was going on.” [s46]

• “I thought there would be more to it, like a beep. But I didn't hear that.” [s47]

• “I thought my picture was being taken.” [s50]

Poster

Participants wanted the poster to provide more information than it did.

• “Would have been nice if it said on the poster that the green light would go on to say it's 

okay.” [s24]

• [Poster was] “a distraction. For a poster that big, there's very little information on it.” [s43]

Scanning Area

One participant commented that the platen was notably small.

• [Platen] “is very small. Kid size” [s1]
NISTIR 7944 Page 27 9/2013

Overall Understanding

Participants noted that they had trouble knowing if they had performed the process correctly 

or completely. They expected timely confirmations regarding when they thought they had 

completed a capture.

• “Kinda had to figure it out." "It wasn't really user friendly. The process is not going to be user 

friendly. I had problems with figuring out what to do. There was nothing to tell me what to do.” 

[s34]

• “Pretty clear, except for the time. But there wasn't a time on the poster, so I just made an 

assumption.” [s37]

• “Am I doing it wrong or correctly? Am I done with the process? Very confusing.” [s39]

• [Used it] “to learn what to do first. Just used the picture. Wasn't sure when it was finished. I 

guess I was expecting some words, like 'Next.'“ [s48]

• “It got the fingerprint. It buzzed, but it was so late you didn't know if you were done or not.” 

[s52]

Miscellaneous

One participant remarked on the table height, which was uncomfortably high for that 

participant. Another participant seemed to expect the rolling aspect of the paper and ink 

fingerprint capture process to be included in this process. Additionally, the lack of timing 

indicators or a feeling of control of the process, such as pressing an “OK” button, was noted.

• The “table was a little high for me. I could reach, but it was hard. Uncomfortable.” [s1]

• “Was a little confused about whether I [put one] finger or all my fingers and which direction to 

roll my fingers.” [s21]

• “The steps were easy to figure out. I just needed to know how long I needed to keep my 

finger on the machine.” [s25]

• “I imagined it to be like an ATM. I was frustrated that there was no timing involved. With 

computers, I know you need to press an OK button to go on, and there wasn't anything like 

that.” [s55]

4.2.3 What guided participants as they used the scanner – self-reported 

After discussing the participant’s labeling of the diagram, the researcher asked the following 

question, “I am interested in what you considered to be the ‘instructions’ for the 

fingerprinting task. What did you use to help guide you when you used the scanner?”

Table 3 below provides counts of the indicators participants reported using to guide them 

through the fingerprint scanning process with respect to their success at having the scanner 
NISTIR 7944 Page 28 9/2013

capture their fingerprints. It is important to note that some participants might have focused 

on the term “instructions” and did not interpret the question to include the entire set of 

instructive indicators. Inconsistencies between spoken comments recorded during the 

scanning process and reported affordance use raise this issue. In any case, the data is reported 

here as recorded immediately following the diagram labeling exercise.

Table 3: Instructional indicators used by participants and capture success

Full set of 

prints

(n=10)

Some 

captured

(n=9)

None 

captured 

(n=43)

Total

Poster 8 8 43 59

Slap Icons 7 0 4 11

LED Lights 3 1 2 6

Beep 0 1 0 1

Participants who captured complete sets of prints reported that they considered either the USVISIT poster, the slap icons on the sides of the scanner platen, or both to be their 

"instructions" for using the scanner. Only 3 of the completely successful participants said 

that the LED lights provided them with instruction, and none regarded the beeps as 

instructive.

Many participants reported relying almost exclusively on the poster for guidance, as 

indicated by Table 4 below. Please note that the caveat given for the previous table regarding 

possible participant focus on the term “instructions” applies to this table as well.

Table 4: Participant reliance on instructional poster and capture success

Full set of prints

n=10

Some prints

n=9

No prints

n=43

All participants

n=62

Poster Only 2 8 37 47

Poster + Other 

Indicator(s) 6 0 6 12

Other Indicator 

Only 2 1 0 3
NISTIR 7944 Page 29 9/2013

4.2.4 Instructive materials and indicators – helpfulness and clarity

In addition to asking participants what they used as instructional indicators, the post-task 

questionnaire asked them to rate (on a five-point scale) the clarity and effectiveness of those 

indicators. Participants’ ratings for what they regarded as “instructions” are shown in Table 

5. 

Table 5: Participants' ratings of the clarity and helpfulness of the US-VISIT poster

Statement Rating Scale Average Rating

The instructions provided were effective in helping 

me complete the fingerprint capture process.

1 = Ineffective

2 = Somewhat effective

3 = Effective

4 = Very effective

5 = Completely effective

2.40 (Somewhat 

effective)

The instructions provided clearly described the 

fingerprint process.

1 = Unclear

2 = Somewhat clear

3 = Clear

4 = Very clear

5 = Intuitive

2.45 (Somewhat 

clear)

The instructions provided were confusing.

1 = Not confusing

2 = Somewhat confusing

3 = Confusing

4 = Fairly confusing

5 = Very confusing

2.00 (Somewhat 

confusing)

Participants reported that the instructions provided were “somewhat effective” but not 

“effective” in helping them complete the fingerprinting task. With respect to clarity, 

participants rated the instructions as being only “somewhat clear” at describing the 

fingerprint process and “somewhat confusing” overall. 

Participants also rated their clarity on various aspects of the fingerprinting process; the 

results are shown in Table 6. Understanding of the slap order was “clear”, while how to 

position one’s self for fingerprinting was “somewhat clear”. Clarity surrounding key 
NISTIR 7944 Page 30 9/2013

milestones within the fingerprinting process (beginning, ending, image capture) were all 

“unclear”.

Table 6: Participants' ratings of their clarity on aspects of the fingerprint process

Statement Rating Scale Average 

Rating

The order of the fingerprint capture was clear.

1 = Unclear

2 = Somewhat clear

3 = Clear

4 = Very clear

5 = Intuitive

3.35

It was clear how to position yourself for the fingerprinting. 2.58

It was clear when the fingerprint image had been taken. 1.84

It was clear when the fingerprint process began. 1.85

It was clear when the fingerprint process ended. 1.87

4.2.5 Confidence and capture success

When asked "How confident are you that you completed the fingerprint task as intended?" on 

the post-task survey, participants gave an average rating of 2.1 (“Somewhat confident”). A 5-

point scale was used, other response choices for this question were as follows: 1 being “Not 

Confident,” 3 being “Confident,” 4 being “Very Confident,” and 5 being “Certain”. 

Participants who successfully captured a full set of prints had an average confidence rating of 

3.2 (“Confident”), while those who were unsuccessful had an average of 1.7 and 1.9, not 

quite at the “Somewhat confident” mark, for those who left some prints and no prints, 

respectively. The confidence levels with their respective standard error calculations are 

shown in Table 7.

Table 7: Participant confidence scores and capture success (mean + SE)

Full set of 

prints

n=10

Some but 

not all prints

n=9

No prints

n=43

Total

n=62

Confidence 3.2 + 0.4 1.7 + 0.4 1.9 + 0.2 2.1 + 0.1

Participants who had a full set of prints captured had a statistically significantly higher level 

of confidence (p<0.01) compared with the other two groups whose participants did not leave 
NISTIR 7944 Page 31 9/2013

a full set of prints (using Student’s t-test to determine if sets of data are significantly different 

from each other). Having said that, none of the participants in this study were particularly 

confident that they had used the scanner correctly. The average confidence scores from 

successful and unsuccessful participants suggest that many people knew or suspected that 

they were not using the scanner correctly and that they felt it was unlikely they had 

successfully captured prints. On average, successful participants were only "confident," 

rather than "very confident" or "certain" that they completed the fingerprinting task as 

intended.

4.3 WHAT PARTICIPANTS FOUND TO BE CONFUSING

When asked on the post-task questionnaire, “What was the most confusing part of the 

process?,” participants provided insight into why their confidence levels were so low. Note 

that some participants provided several items they found confusing.

Overwhelmingly, 41 of 62 participants cited issues related to perceived lack of guidance and 

feedback during their progression through the task, e.g., how long to leave fingers on the 

platen for the capture to complete and when to move to the next slap, were given most often 

as confusing aspects of the overall task. Participant comments on this topic include the 

following:

• “How long to hold my fingers down and if the image was captured successfully.” [s5]

• “When to proceed to the next step; when the scanning began.” [s6]

• “Needed a clear signal of where to switch fingers” [s7]

• “I didn't know when images were completed nor when to continue.” [s9]

• “What, if anything, to do with the buttons, whether to wait for a beep or instructions. How long 

to wait between procedures.” [s10]

• “Unclear of the timing in the fingerprinting process. Unsure if my fingerprints have been

captured.” [s11]

• “To know when the image was captured or not and when to move on to the other side.” [s12]

• “Knowing when an image had been taken” [s14]

• “Not knowing if I did things correctly, if the scan actually worked during each process, when 

to start and when to finish.” [s15]

• “Know when the process started. When to move on to the next step. The next step (how long 

to leave my hand on the machine). When process is complete.” [s23]

• “Not sure when to move to the next position of fingerprint.” [s33]

• “Not being guided and not knowing if the scan had taken or when it was over.” [s46]

• “Not knowing if the scanner was reading the image; not knowing if/when finished” [s58]
NISTIR 7944 Page 32 9/2013

Where to place fingers on the platen was also noted as an area of confusion. Participants 

reported the following: 

• “Where is the rectangle part you're supposed to work within?” [s8]

• “Knowing where to place my fingers” [s16]

• “Where exactly on the glass to place digits.” [s44]

• “Where to place your fingers. Is anywhere ok?” [s59]

Other participants cited the lack of instruction to be the most confusing aspect of the task 

with the following comments:

• “Not having some written instructions.” [s2]

• “Lack of instruction on how the machine worked.” [s3]

• “Not having clear instructions” [s13]

• “No instructions of start/finish” [s47]

• “Only instructions were which hand to use -- not how long --or follow the light -- listen for the 

beep, etc.” [s56]

Some participants expressed that the LED lights were the most confusing aspect for them and 

provided the following comments:

• “The lights did not if all four lights needs to be green when I put only one finger.” [s27]

• “Figuring out that the lights individually indicated it was sensing your prints they look like 

progress bars.” [s43]

• “I didn't understand what the lights mean” [s57]

One participant wanted a way to correct a perceived mistake and stated it this way: 

• “If you make a mistake how do you reset the system.” [s59]

Three of the ten fully successful participants found confusing aspects of the task as well, and 

provided the following insights: 

• “Not sure it actually scanned my fingerprints. If it could say scan complete that would tell me 

for sure that it was completed properly.” [s32]

• “When I had to go to the next step.” [s34]

• “Figuring out on which part of the glass to place my fingers. It was obvious I was doing it 

wrong but not super intuitive how to do it right.” [s45]
NISTIR 7944 Page 33 9/2013

Several participants who did not manage to have any fingerprints captured, had interesting 

observations on what they found most confusing. Their comments follow below: 

• “Nothing” [s4]

• “The first step. The rest was clear” [s24]

• “None” [s29]

• “They was hardly any buzzing when I completed the task. I did not know I was finished when 

I completed my task.” [s52]

4.4 PARTICIPANT-REPORTED LESSONS LEARNED

The post-task questionnaire asked participants, “Would you do anything differently next 

time?” Nineteen of the 62 participants said they wouldn’t do anything differently. Of these 

participants, only three were from the fully successful group of ten. Of the remaining seven 

fully successful participants, two did not provide feedback to this question, while another 

merely responded with “Yes”. The remaining four participants provided the following 

comments:

• “Take a closer look at visual markings on the pad” [s16]

• “Yes, I would not put my whole hand on the screen, only the four fingers as indicated in the 

instructions.” [s34]

• “Start off pressing curved fingers, not held straight like in the graphic.” [s43]

• “Position my fingers in the target box” [s54]

19 other participants said that they would request clearer feedback, instructions and/or 

assistance from the system operator either before or during the fingerprinting process. Some 

participants were more specific than others about how and what they would request. 

Representative comments follow:

• “Request clearer instructions” [s1]

• “Inquire about the time necessary to capture the fingerprints. Inquire about the signals that 

ensured successful capture of the fingerprints. Inquire about the placement of my finger on 

the machine” [s11]

• “Ask questions before beginning. Step by step instructions.” [s15]

• “Ask if I was doing it right as I put my different fingers on the scanner” [s26]

• “Maybe ask when to start and if I would be told when to move on.” [s46]

• “Ask questions” [s56]
NISTIR 7944 Page 34 9/2013

Of these 19, three specifically wanted verbal instruction – indicating a lack of confidence in 

their use of the icons, lights, beeps, and written instruction to proceed through the task. These 

comments are provided next:

• “Seek verbal guidance” [s6]

• “I also needs a voice that give step by step directions.” [s52]

• “Voice instructions timed” [s55]

Some participants noted that they would look for certain features on the scanner or change 

their behaviors if they could perform the fingerprinting process over again. Their comments 

included the following:

• “Make sure all the lights turned green before moving on.” [s4]

• “Pay attention to the red & green light” [s7]

• “Take a closer look at visual markings on the pad” [s16] (Noted previously)

• “Maybe do one finger at a time and wait until all of the lights turned green.” [s21]

• “Look at the color and patterns of the light on the scanner” [s24]

• “Wait for a beep. ON first use, I thought I was finished when I saw 4 lights.” [s28]

• “Yes, I would not put my whole hand on the screen, only the four fingers as indicated in the 

instructions.” [34] (Noted previously)

• “Start off pressing curved fingers, not held straight like in the graphic.” [s43] (Noted 

previously)

• “Position my fingers in the target box” [s54] (Noted previously)

Some participants had mistaken impressions of changed behaviors that would be successful 

if they could perform the fingerprinting process over again.

• “I would first press the button indicating the fingerprints in play. I would then be careful to not 

let the fingerprints extend above (beyond) the four dashes on the side.” [s10]

• “Move on after putting my 4 fingers down, not wait for green lights” [s19]

• “Check to see if the displays on the sides are buttons” [s51]

4.5 OTHER EFFECTS

4.5.1 Effects of subject demographics on capture success

Table 8 provides the capture success of participants shown with respect to gender. Of the 10 

participants who were fully successful at completing the task, 3 were female and 7 were 

male. For participants who were partially successful, 3 were female and 6 were male. Finally, 

of the 43 participants who did not have any prints captured, 26 were female and 17 were 

male. Although it has been shown in earlier studies that men are more likely to capture 
NISTIR 7944 Page 35 9/2013

quality prints than women [8], no further analysis of an effect from gender is warranted in 

this data due to the small number of female participants who were fully and partially 

successful at capturing fingerprints. 

Table 8: Capture success by gender

Full set of prints

n=10

Some but not 

all prints

n=9

No prints

n=43

Total

n=62

Female 3 3 26 32

Male 7 6 17 30

Table 9 shows the average age of participants with respect to how successful they were in 

having fingerprints captured. The average age of the participants in this study was 38.3 years 

+ 4.9. Participant age had no statistically significant effect on capture success in this study.

Table 9: Capture success and age (Mean + SE)

Full set of 

prints

n=10

Some but 

not all prints

n=9

No prints

n=43

Total

n=62

Age 35.4 + 11.2 46.2 + 15.4 37.4 + 5.7 38.3 + 4.9

4.5.2 Print quality – threshold and results

Overall, the fingerprints that were captured by the scanner were of good quality. Table 10

shows the average quality score of captured prints, using the NFIQ algorithm. These were

quite good – close to the optimal NFIQ score of 1. 

One factor affecting this high average score, was that the scanner software was set to capture 

and store fingerprint images with a threshold score of 3 or better for its proprietary quality 

assessment, resulting in high quality prints that were captured.
NISTIR 7944 Page 36 9/2013

Table 10: Fingerprint capture success and quality (NFIQ)

Full set of 

prints

n=10

Some but not 

all prints

n=9

No prints

n=43

All prints 

captured

n=19

Average Print 

Quality Score 

(NFIQ)

1.79 1.55 n/a 1.68

4.5.3 Number of attempts to make a successful slap

We observed a difference in number of slap attempts and capture success. The average 

number of attempts for each capture success group is displayed in Table 11 below.

Table 11: Average number of slap attempts and capture success

Full set of prints

n=10

Some but not all

n=9

No prints

n=43

Right slap 

attempts 4.3 2.3 1.7

Right Thumb 

Attempts 2.0 1.4 1.3

Left Slap 

Attempts 1.8 2.2 1.4

Left Thumb 

Attempts 1.5 1.4 1.2

Total 9.6 7.4 5.6

Notably, participants in the fully successful group tended to make more attempts on the first 

slap and once successful, the number of attempts to complete each subsequent slap generally 

trended downward. On average, participants who succeeded at capturing a full set of prints 

needed 4.3 attempts to complete the initial right slap and 2 attempts to complete the right 

thumb slap. They needed slightly fewer tries to capture the left slap (1.8) and 1.5 for the left 

thumb slap. The 10 participants (6.2 % of the total) who captured complete sets of prints 
NISTIR 7944 Page 37 9/2013

made a total of 96 slap attempts (40 would be the fewest expected – one attempt for each slap 

for each participant), with an average of 9.6 slaps each.

Other participants made fewer attempts on the initial slap and were not as successful 

capturing fingerprints overall.

4.5.4 Effects of software crashes

Some unexpected interactions between the system configuration and LSMS scanning 

software led to system crashes. Although we performed extensive testing on the scanner after 

all our participants were finished going through the procedure, we were unable to 

consistently reproduce the error and are unsure of the cause. Crashes did not occur during use 

of the system prior to participant involvement.

Twelve of the 62 participants – from both successful and unsuccessful groups – experienced 

this problem. When the system crashed, the researcher would have participants sit in a chair 

away from the fingerprinting device and ask them questions from the post-task questionnaire 

while he/she restarted the system. From what we observed, the crashes had no noticeable 

effect on their performance during the scanning process, or on the views they expressed 

during and after the process. 

4.5.5 Effects of scanner height on capture success

Scanner height did not have any noticeable effect on capture success, image quality, or user 

confidence. Previous studies [9] have shown that a large number of trials, several hundred, 

are typically performed to see the effect of table height on capture success. Since so 

relatively few of the participants in this study were successful, it would have been surprising 

to see the effect.

Although an effect was not discernible in the data, one participant mentioned the scanner 

height as being too high in the following comment, “[The] table was a little high for me. I 

could reach, but it was hard. Uncomfortable.” [s1]. While another participant was observed 

standing on her tip toes to look at the scanner while attempting to perform the assigned task.

5 DISCUSSION OF THE OBSERVATIONS

From the data, several themes emerge and are discussed below. All are related to the 

effectiveness of capturing a quality fingerprint. In this study, age, gender, scanner height and 
NISTIR 7944 Page 38 9/2013

software crashes did not have statistically significant effects, although previous, larger 

studies have shown effects of age, gender and scanner height.

5.1 WILLINGNESS TO EXPERIMENT

Participants who succeeded in capturing all ten fingerprints made more attempts to complete 

each slap on average than participants who captured only partial sets of prints or no prints at 

all, data shown in Section 4.5.3. Successful participants appeared to use their slap attempts to 

learn the proper use of the scanner through experimentation, examining and learning the 

purpose of the LED lights, slap icons, and beeps as they did so. Their willingness to 

experiment with the scanner may well have contributed to their success.

5.2 QUALITY THRESHOLD

The quality acceptance setting used by LSMS appears to have winnowed the set of scanned

fingerprints into a set of captured fingerprints with generally high quality, as assessed with 

the NFIQ algorithm. There is no doubt that if the quality threshold for the scanner had been 

set to allow the capture of prints of lower quality, it is possible that more participants may 

have captured more prints. What is not clear is 1) if the additional prints captured would have 

been of acceptable quality for DHS purposes and 2) if participants would have understood 

the process better or just happened to capture more prints. Since many participants did not 

notice or interpret correctly the instructional indicators, the overall positive effect of a 

reduced quality threshold remains questionable.

That said, for the relatively small number of fingerprints the scanner did capture, it was 

effective at capturing prints of adequate quality.

5.3 LACK OF CLARITY

Because participants did not receive any guidance, instruction, or assistance from the

researcher/operator when they used the scanner, they had to rely on the US-VISIT 

instructional poster, slap icons, LED lights, and beeps for instructions and feedback during 

the task. Often participants, when they did notice the affordances, had difficulty interpreting 

their meanings. This lack of clarity of the affordances’ meanings likely led to the low 

confidence ratings, shown even among successful participants. For example, [s32] who 

captured all prints commented: “Not sure it actually scanned my fingerprints. If it could say 

‘scan complete’ that would tell me for sure that it was completed properly.” Another 

indication of this lack of clarity was revealed by 3 participants who suggested that 

instructions should be presented by a person, e.g., “someone telling you the steps,” [s21] 

when asked for any additional comments or suggestions.
NISTIR 7944 Page 39 9/2013

That said, participants did not relate to all of the instructional indicators in the same way, 

although certain patterns emerged. We discuss our findings related to each of the 

instructional indicators below.

5.3.1 Instructional poster

In their post-task debriefing, most participants (59 of 62) said that they used the US-VISIT 

poster as an instructional indicator to help guide them through using the fingerprint scanner. 

We discovered that some successful participants used the poster in combination with other 

cues – such as the slap icons and LED lights – to help them use the fingerprint scanner 

effectively, while unsuccessful participants relied more heavily on the poster to guide them. 

This result was consistent with findings from a previous fingerprinting study involving a 

similar instructional poster [11]. There are two reasons why the poster may have negatively 

affected the performance of participants who relied heavily on it.

First, while the poster indicated proper finger positioning for the model of scanner being 

used, it still left many participants unsure of how to place their fingers properly. The graphics 

on the poster depicted the scanning area (on the lower half of the scanner platen) as being 

darker than the non-scanning area: several participants remarked that the reverse was true on 

the scanning device. Some participants may also have been confused because, while the 

pictures on the US-VISIT poster seemed to indicate that one should hold one’s fingers 

straight when presenting a four-finger slap, not everyone could fit the pads of their fingers in 

the scanning area when holding them this way – some individuals must bend the middle 

finger slightly to bring all four fingers into the scanning area.

Second, the poster only went as far as explaining the proper slap sequence and finger 

positioning. It did not say how long participants should hold their fingers on the platen or 

how much pressure they should apply. It also did not mention or explain features on the 

scanner that participants could have used for guidance and feedback – the slap icons, LED

lights, and beeps. This is likely part of the reason why many participants did not correctly 

interpret the first two features, and did not know that they should expect the third as 

confirmation of a successful capture.

5.3.2 Slap icons

When filling out the blank diagram of the scanner, 58.1 % of participants (36 of 62),

indicated they noticed the slap icons along the sides of the scanner platen, however, only 18 

(29.0 %) labeled them correctly, i.e., could relate their function. Further, only 11 (17.7 %)

reported using the icons for guidance through the task. Of the participants who noticed, but 

did not discern the actual function of the slap icons, some said the slap icons were buttons, 
NISTIR 7944 Page 40 9/2013

mistaking them for features on the scanner that could support interaction, rather than 

providing guidance. 

In a broad sense, the purpose of the icons was intended to provide users with the slap order. 

Whether participants used the icons, the poster, or a combination of both, participants 

typically presented slaps in the proper order. Since this was presented quite clearly on the 

poster, there is no way to discern if the slap icons succeeded in supporting this broad 

purpose. Beyond the order, the lack of guidance regarding which slap the scanner expected at 

any particular time during the overall task, left most participants expressing confusion. [s14]

related it this way, “Didn't notice the lights changing at all. Wasn't clear if these need to be 

pressed. Assumed when it lights up, the image was taken. Not too clear.” In this respect the 

slap icons generally provided little or no guidance.

5.3.3 LED lights

All of the ten participants who captured full sets of prints marked the LED lights on the 

scanner diagrams given to them after the fingerprinting task, although only 7 of them labeled 

the LED lights correctly. Most participants who noticed some of the LED lights turning from 

red to green during the fingerprinting process either assumed that the LED lights were 

progress indicators or were showing that their slap had been captured by the scanner.

Participants who said they thought the LED lights were progress indicators typically had 

placed their fingers only slightly incorrectly; the problem was usually the middle finger, 

which reached out of the scanning area. Some participants inferred that the LED lights were 

related to placement correctness; and, these participants were likely to make multiple 

attempts to present a slap. As previously noted, the more attempts a participant made, the 

more likely he/she was to succeed in capturing a partial or complete set of fingerprints.

5.3.4 Beeps

When they received them, many participants were able to deduce the correct meaning of the 

beeps, partially because they expected some sort of confirmation of the capture process. 

However, some of these participants remarked that the confirmation came so much later after 

they expected it, that it actually caused confusion as to what was actually happening in the 

process. One participant related the experience in this way, “I don't associate them with 

anything that was going on.” [s46]
NISTIR 7944 Page 41 9/2013

5.4 PULLING IT ALL TOGETHER - TIMING CUES

Overall, participants reported being unclear about when the fingerprint process started, 

ended, when a fingerprint was actually captured (shown in Table 6), and by extension, when 

to progress to the next slap. This lack of clarity regarding cues in the process was decidedly 

cited the most often when participants were asked to comment on what they found the most 

confusing (Section 4.3). It may have contributed to the generally low confidence ratings as 

well. Comments given by participants during the fingerprint capture task, provided in the 

Overall Understanding category in 4.2.1, often reflect participants’ ability to correctly 

interpret one or two of the indicators, but correctly interpreting them all and using those 

correct interpretations to move through the task effectively, was much rarer. Even 

participants who were successful at capturing fingerprints remarked on the lack of timing 

cues to support them in completing the task successfully and confidently.

5.5 OVERALL SUITABILITY OF SCANNER FOR SELF-SERVICE USE

It is clear that the poster and scanner affordances alone did not provide the information and 

cues most participants needed to present all their slaps correctly. The US-VISIT poster 

provided helpful – but not complete – instructions on what participants were expected to do 

during the fingerprinting process. Many participants did not notice the slap icons and LED 

lights or, if they did, misinterpreted what those things meant. These factors contributed to a 

high failure rate in terms of successful print capture: 43 of our 62 participants ( 69.4 %) did 

not succeed in capturing any prints at all.

Since this failure rate would be unacceptable for a self-service fingerprint capture device in 

the real world (or indeed any fingerprint capture device), it is evident that the scanner and 

instructional materials used in this study, if implemented in the US-VISIT program would be 

insufficient to serve that purpose on their own.

6 CONCLUSION

In the real world, users receive guidance and feedback from a Customs and Border 

Protection officer when undergoing the fingerprinting process with the scanner and poster 

employed in this study. Based on our observations and feedback from participants, removing 

the guidance of a human operator from the equation makes it much more difficult – even 

impossible – for users to successfully present their fingerprints to the scanner in such a way 

that the scanner can capture a full set of fingerprint images. The US-VISIT poster and 
NISTIR 7944 Page 42 9/2013

scanner affordances alone did not provide users with the information and cues they needed to 

evaluate (and, if necessary, correct) their performance.

A self-service fingerprinting solution will have to include considerably more user feedback, 

instruction, or both than offered by the fingerprint scanner and US-VISIT poster used in this 

study. Developing a truly effective self-service solution will require extensive research and 

testing: this study helps to define the parameters for that future work.
NISTIR 7944 Page 43 9/2013

7 REFERENCES

[1] ISO 9241-210:2010 Ergonomics of human-system interaction – Part 210: Humancentred design for interactive systems.

[2] Koslowski, R. (2005). Real challenges for virtual borders: The implementation of 

US-VISIT. Newark, NJ: Migration Policy Institute. Retrieved February 27, 2013 from 

http://www.migrationpolicy.org/pubs/Koslowski_report.pdf.

[3] NIST Information Technology Laboratory, Information Access Division, Image 

Group. (2012, August 8). NIST Biometric Image Software. NIST Information 

Technology Laboratory. Retrieved February 27, 2013 from 

http://www.nist.gov/itl/iad/ig/nbis.cfm.

[4] Norman, D. (2007). Affordances and design. Jnd.org. Retrieved February 27, 2013 

from http://jnd.org/dn.mss/affordances_and_design.html

[5] Micheals, R., Stanton, B., Theofanos, M., and Orandi, S. U.S. Department of 

Commerce, National Institute of Standards and Technology (NIST). (2006). A 

taxonomy of definitions for usability studies in biometrics (NIST IR 7378). Retrieved 

February 27, 2013 from http://www.nist.gov/customcf/get_pdf.cfm?pub_id=50911

[6] Tabassi, E., Wilson, C., and Watson, C. U.S. Department of Commerce, National 

Institute of Standards and Technology (NIST). (2004). Fingerprint image quality

(NIST IR 7151). Retrieved February 27, 2013 from

http://www.nist.gov/customcf/get_pdf.cfm?pub_id=905710.

[7] Theofanos, M., Stanton, B., Sheppard, C., Micheals, S., Choong, Y., Wydler, J., 

Mangold, K., Steves, M., and Morse, E. U.S. Department of Commerce, National 

Institute of Standards and Technology (NIST). (2008). Assessing face overlay (NIST 

IR 7578). Retrieved February 27, 2013 from

http://www.nist.gov/customcf/get_pdf.cfm?pub_id=902148.

[8] Theofanos, M., Micheals, R., Scholtz, J., Morse, E., & May, P. (2006, April). Does 

habituation affect fingerprint quality? Proceeding CHI '06 Extended Abstracts on 

Human Factors in Computing Systems, 1427-1432. doi: 10.1145/1125451.1125714.
NISTIR 7944 Page 44 9/2013

[9] Theofanos, M., Orandi, S., Micheals, R., Stanton, B., and Zhang, N. F. U.S. 

Department of Commerce, National Institute of Standards and Technology (NIST). 

(2007). Effects of scanner height on fingerprint capture (NIST IR 7382). Retrieved 

February 27, 2013 from http://www.nist.gov/customcf/get_pdf.cfm?pub_id=50903.

[10] Theofanos, M., Stanton, B., Sheppard, C., Micheals, S., Zhang, N. F., Wydler, J., 

Nadel, L., and Rubin, W. U.S. Department of Commerce, National Institute of 

Standards and Technology (NIST). (2008). Usability testing of height and angles of 

ten-print fingerprint capture (NIST IR 7504). Retrieved February 27, 2013 from

http://www.nist.gov/customcf/get_pdf.cfm?pub_id=152149.

[11] Theofanos, M., Stanton, B., Orandi, S., Micheals, R., and Zhang, N. F. U.S. 

Department of Commerce, National Institute of Standards and Technology (NIST). 

(2007). Usability testing of ten-print fingerprint capture (NIST IR 7403). Retrieved 

February 27, 2013 from http://www.nist.gov/customcf/get_pdf.cfm?pub_id=51123.
NISTIR 7944 Page 45 9/2013

APPENDIX A: USER DEMOGRAPHIC SURVEY

Biometric Modality: _________________ Date: ___________

Demographic Questionnaire

1. Age: ____________

1. Gender: (circle one) male female

2. Height: ______________ feet ____________ inches 

3. Ethnicity: _______________________________________

4. Profession: ______________________________________________ 

5. Country of Origin: ______________________________________________ 

6. Which hand do you use to write? (circle one) right left both

7. Have you ever had your biometrics captured before? (circle one) yes no 

If yes, check all that apply:

___ Fingerprinted with ink/paper

___ Fingerprinted electronically
NISTIR 7944 Page 46 9/2013

___ Palm Print

___ Eye Scan

___ Face Image 

___ Voice 

___ Hand geometry 
NISTIR 7944 Page 47 9/2013

APPENDIX B: FINGERPRINT SCANNER DATASHEET

Scanner height: _____ high _____ low Participant #_________

PRESENTATION ORDER 

Order # Attempts Collected? Collected correctly? Comments / Questions / Behaviors

Right slap 1 2 3 4 1 2 3 4 Y N Y N

Right thumb 1 2 3 4 1 2 3 4 Y N Y N

Left slap 1 2 3 4 1 2 3 4 Y N Y N

Left thumb 1 2 3 4 1 2 3 4 Y N Y N

SCANNER INTERACTIONS
NISTIR 7944 Page 48 9/2013

Notice? Understand? Comments / Questions / Behaviors

Red/green 

lights y / n / u y / n / u

Icon lights y / n / u y / n / u

Notice? Understand?

Used 

whole 

glass

Used 

bottom 

scan 

area Comments / Questions / Behaviors

Scanning 

area y / n / u y / n / u

Receive beep? Notice beep? Understand meaning? Comments / Questions / Behaviors

Beep y / n / u y / n / u y / n / u
NISTIR 7944 Page 49 9/2013

Notice? Understand?

Instructions 

seemed to 

dominate Comments / Questions / Behaviors

Poster 

instructions y / n / u y / n / u y / n / u

DIAGRAM LABELING

Notice lights? Y N What did they say?

Any labeling of lights? Y N

Correct labeling? Y N

Notice icons? Y N What did they say?

Any labeling of icons? Y N

Correct labeling? Y N
NISTIR 7944 Page 50 9/2013

Notice beep? Y N What did they say? 

Any description of beep? Y N

Correct description? Y N

Participant considered instructions to be: Poster / Lights / Icons / Beeps

OVERALL UNDERSTANDING 

Got it: Could explain to 

someone else 

how to do it 

Muddled through, could not 

explain to someone else

Grasped 

after scanning Never got it, no data
NISTIR 7944 Page 51 9/2013

DEBRIEF QUESTIONS 

Trip to _______________________________

Entry place ___________________________

MM/YY ____________________

Biometrics captured before? 

_____ Yes

_____ No 

If yes, what, why: 
NISTIR 7944 Page 52 9/2013

APPENDIX C: POST-TASK SURVEY

Subject #: _________________ Date: ________________

POST-TASK SURVEY

1. The instructions provided were effective in helping me complete the fingerprint 

capture process. 

1 2 3 4 5

Ineffective Somewhat 

effective

Effective Very effective Completely 

effective

2. The instructions provided clearly described the fingerprint process. 

1 2 3 4 5

Unclear Somewhat clear Clear Very clear Intuitive

3. The instructions provided were confusing.

1 2 3 4 5

Not Confusing Somewhat 

confusing

Confusing Fairly confusing Very confusing
NISTIR 7944 Page 53 9/2013

4. The order of the fingerprint capture was clear.

1 2 3 4 5

Unclear Somewhat clear Clear Very clear Intuitive

5. It was clear how to position yourself for the fingerprinting. 

1 2 3 4 5

Unclear Somewhat clear Clear Very clear Intuitive

6. It was clear when the fingerprint image had been taken.

1 2 3 4 5

Unclear Somewhat clear Clear Very clear Intuitive

7. It was clear when the fingerprint process began.

1 2 3 4 5

Unclear Somewhat clear Clear Very clear Intuitive

8. It was clear when the fingerprint process ended. 

1 2 3 4 5
NISTIR 7944 Page 54 9/2013

Unclear Somewhat clear Clear Very clear Intuitive

9. How confident are you that you completed the fingerprint task as intended?

1 2 3 4 5

Not confident Somewhat confident Confident Very confident Certain

10. Would you do anything differently the next time?

11. What was the most confusing part of the process?

12. Do you have any additional comments on the process? 

NOTE: This survey contains collection of information requirements subject to the Paperwork 

Reduction Act. Notwithstanding any other provision of the law, no person is required to respond to, 

nor shall any person be subject to a penalty for failure to comply with, a collection of information 

subject to the requirements of the Paperwork Reduction Act, unless that collection of information 

displays a currently valid OMB control number. The estimated response time for this survey is 15
NISTIR 7944 Page 55 9/2013

minutes. The response time includes the time for reviewing instructions, searching existing data 

sources, gathering and maintaining the data needed, and completing and reviewing the collection of 

information." OMB Number: 0693-0043 Expiration: 10/31/2012.