Counter height and fingerprint scanner angle

1. Mary Theofanos Brian Stanton Counter height and fingerprint scanner angle A case study on the importance of experimental rigor

2. Human Computer Interaction2 Views of the Same System Engineering Participant presents Attempt starts System starts capture Capture Attempt Capture repeated if unacceptable Attempt ends Next attempt (acceptable attempt) Capture thresholding Human Factors Time 2

3. Why is experimental rigor so important in our program? • Test must be valid • That we are really testing what we say we are • Results must be repeatable • Everything documented so someone else can replicate • Results must be generalizable • We usually can’t test everyone so we want to test a sample and generalize to a larger population Our results are fielded quickly

4. Why is rigorous design necessary? Think of it as taking noise out of the system

5. Experimental Design • Introduction • Method • Participants • Equipment • Procedure • Results

6. Introduction What question does this study try to answer?

7. Problem: • United States Visitor and Immigrant Status Indicator Technology (US-VISIT) transitioning to a 10-print process (new scanner) • Existing counters too tall for a 10 print • Can’t change the existing counter heights ($) • US-VISIT needs: • Throughput – process travelers as quickly as possible • Quality – collect best possible fingerprint images • Customer Service – concerned for travelers comfort and safety

8. How about angling the scanner? Question: Given current surface heights, what is the “best” angle for a electronic fingerprint scanner? heights “best” angle

9. Heights

10. Heights • Scanner Model at three heights • 39” • 45” Practical Midpoint • 49” 49” 45” 39”

11. Angles • With CAD Software looked at a Range of Angles at the three Heights • Example: 39”

12. Angles • Selected Range of Angles • 0° • 10 ° • 20 ° • 30 ° 0° 10° 20° 30°

13. 3 Heights and 4 Angles • Heights • 39” • 45” • 49 • Angels • 0° • 10 ° • 20 ° • 30 °

14. Method What to collect and how to collect it?

15. Who does this study address? Representative of The flying public

16. What characteristics of the traveling public are important? • Age • Height • Gender • Ability

17. Age • People between the ages of 14 – 79 are required to present prints when arriving in the US.

18. Height 95th Percentile Male 184.9 cm. (72.8 in.) 5th Percentile Female 149.9 cm (59.0 in) 50th Percentile 166.6 cm (65.6 in)

19. Gender • Equal mix male and female

20. Ability • Assumption: disabled travelers will have an alternative method.

21. Participants • Representative of the traveling public • 14 -79 Years • Even numbers of men and women • Heights ranging from 150 cm. to 185 cm.

22. Participants’ Rights Institutional Review Board …to review the ethical acceptability of all research conducted where human subjects are used… • To protect the physical and psychological well-being of subjects • To serve as a safeguard to protect against errors in ethical judgment • To assure human subject testing is in compliance with Part 27 of Title 15 of the Code of Federal Regulations • To protect the privacy of the participants

23. Equipment Scanners

24. Two Electronic Fingerprint Scanners • Each was compliant with Department of Homeland Security’s requirements and was supplied to us. • Capable of taking a 10 print • 6” x 6” x 6”

25. Equipment Table

26. Equipment Adjustable Table

27. Equipment Scanner Angle

28. Equipment Scanner Angle

29. Experimental Design Now we know the heights and angles and all the equipment, how do we put them together?

30. Between Variables and Within Variables • Between: Each participant is tested on one condition • Within: Each participant is tested on every condition (repeated measures) It takes some analysis to know when and how to use them.

31. Between Participant Design Height Angle 39” 0° 45” 49” 0° 0° 39” 10° 45” 49” 10° 10° 39” 20° 45” 49” 20° 20° 39” 30° 45” 49” 30° 30°

32. Within Participant Design Height Angle 39” 0° 45” 49” 0° 0° 39” 10° 45” 49” 10° 10° 39” 20° 45” 49” 20° 20° 39” 30° 45” 49” 30° 30°

33. Mixed Design Height Angle Angle Angle Angle Angle Height Height Angle Angle Angle Angle Angle Angle Angle Angle

34. Experimental Design • 4 Angles • 3 Heights • 3 x 4 mixed design • 12 possible combinations • Each person gets a height and each angle 49” 45” 39”

35. Experimental Design • Since each person gets every angle, order of presentation was counterbalanced • Right/Left start Randomly Selected 49” 45” 39”

36. What do you collect and how? Data Collection

37. What to measure? Given current surface heights, what is the “best” angle? • Definition: ISO 13407:1999 • “Usability: The extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency, and satisfaction in a specified context of use.”

38. What to measure? Given current surface heights, what is the “best” angle? Best = • US-VISIT needs: • process travelers as quickly as possible • Efficiency – : Timing – Time to complete task • collect best possible fingerprint images • Effectiveness – : Quality – How good were the prints • concerned for travelers’ comfort and safety • Satisfaction –: Comfort - Questionnaire effectiveness efficiency satisfaction

39. Timing Opportunity (“please place your hand on the scanner”) Participant presents Attempt starts System starts capture System Capture Attempt System ends capture (“Please remove hand from scanner”) Attempt ends Participant Next attempt (acceptable attempt) Capture thresholding Time

40. Data: How many participants? 12 prints/angle

41. Data 12 prints/angle × 4 angles = 48 prints/height

42. Data 12 prints/angle × 4 angles = 48 prints/height × 20 people (120 people total) = 960 prints per height × 3 heights = 2,880 prints/scanner × 2 scanners = 5,760 total prints

43. Demographics • Age • Gender • Handedness • Right Handed • Left Handed • Ambidextrous • Height

44. Questionnaire • Which angle did you find most comfortable? • 0 degrees • 10 degrees • 20 degrees • 30 degrees • Which angle did you find least comfortable? • 0 degrees • 10 degrees • 20 degrees • 30 degrees •  Please rank the following angles in order of preference by writing a 1, 2, 3 or 4 next to each angle. 1 is most preferred, 4 is least preferred. •   0 degrees • 10 degrees • 20 degrees • 30 degree

45. Detailed Protocol and Procedures • Two teams • Two identical collection platforms • Backups for each system and device • Run throughs and dry runs • Formal schedules • Test scripts • Explicit instructions and procedures • Observation forms • Completed the testing (120 participants in 2 weeks)

46. Results Above all be humble in the face of the data

47. Efficiency: Task Time Scanner A For each response variable of time we examined the factors of angle, table height, and participant height We found: No significant effect due to angle on the time required to complete fingerprint task Scanner B Significance for Time ("+" : p<0.05)

48. Effectiveness: Fingerprint Quality • Determining Fingerprint Quality of a slap is controversial • Performed the analysis 3 ways for completeness • No significant effect on Quality due to Angle

49. User Satisfaction Shorter participants indicated that the flat angle was the least comfortable Taller participants indicated that the 30° angle was least comfortable.

50. Observational Data • Participant Performance • Scanner Performance