TEST DATA ANALYSIS. Presented by. The National Center for Credibility Assessment

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1 TEST DATA ANALYSIS Presented by The National Center for Credibility Assessment April 2011

2 OBJECTIVES Identify and discuss 12 current diagnostic features used in evaluating data for all three physiological waveforms: Respiration Five RLL features One non-rll feature 2

3 OBJECTIVES Diagnostic Features Electrodermal Activity (EDA) One primary feature Two secondary features Cardiovascular One primary feature Two secondary features 3

4 OBJECTIVES Review current scoring procedures for each physiological waveform using 3 & 7 position numerical scales 4

5 HISTORICAL PERSPECTIVE In , Mr. Don Krapohl and Dr Stuart Senter, NCCA Research Division, accomplished extensive literature review to determine how many of the 20 diagnostic features (at that time) could be validated through research 5

6 HISTORICAL PERSPECTIVE Their exhaustive review indicated 12 diagnostic features could be supported by replicated research: Respiration (6 features): RLL: Apnea-blocking, suppression, progressive decrease in amplitude, decrease in rate and change in I/E ratio Non-RLL: Temporary increase in baseline 6

7 HISTORICAL PERSPECTIVE Krapohl & Senter s research (cont d): Electrodermal activity (EDA) (3 features): EDA amplitude EDA complexity EDA duration Cardiovascular (3 features): Baseline arousal (phasic response) Duration Decrease in rate (pulse rate deceleration) 7

8 HISTORICAL PERSPECTIVE On 23 Aug 2006, extensive changes were incorporated into NCCA s curriculum 8

9 RESPIRATORY SYSTEM 9

10 RESPIRATORY WAVEFORM Typically, the normal resting cyclic rate is 12 to 18 breaths per minute. However, this rate may vary due to a person's physical attributes and/or physical conditioning. 10

11 RESPIRATORY WAVEFORM Respiratory changes may be considered responses when occurring in a timely manner to an applied stimulus (reviewed test question) and There is no excessive noise on the signal of interest at stimulus onset 11

12 RESPIRATORY WAVEFORM What is considered a timely response in the respiratory tracing? Should occur within Response Onset Window (ROW): Stimulus onset to include first complete respiratory cycle past answer cycle 12

13 RESPIRATORY WAVEFORM Response Onset Window 13

14 RESPIRATORY WAVEFORM Five respiration line length (RLL) diagnostic features: Apnea - blocking Decrease in rate Change in I/E ratio Decrease in amplitude Progressive decrease in amplitude 14

15 RESPIRATORY WAVEFORM What is RLL? Respiration Line Length (RLL): Procedure for analysis of respiratory tracings. RLL is determined by taking response for specified period of time and visually stretching response into straight line. NCCA utilizes equivalent response window of evaluation 15

16 RESPIRATION LINE LENGTH In RLL procedure, shorter line length signifies more intense or significant response and will be assigned numerical value. 16

17 RESPIRATORY WAVEFORM RLL Window of Evaluation 20 Seconds Default Window of Evaluation Value = +1 Value = +1 17

18 RESPIRATORY WAVEFORM RLL diagnostic features 18

19 RESPIRATORY WAVEFORM Feature 1: Apnea-Blocking (Suppression) l l - Notes: 1. Feature occurs near end of exhalation portion of respiratory cycle. 2. Apnea-blocking feature does not drop significantly below established baseline 19

20 RESPIRATORY WAVEFORM Feature 2: Decrease in Rate l l - 20

21 RESPIRATORY WAVEFORM Feature 3: Change in I/E Ratio l l - 21

22 RESPIRATORY WAVEFORM Feature 4: Decrease in Amplitude (Suppression) l l - 22

23 RESPIRATORY WAVEFORM Feature 5: Progressive Decrease in Amplitude (Suppression) l l - 23

24 RESPIRATORY WAVEFORM Evaluation Procedures If RLL applies to all comparative responses in same analysis spot: Determine response window of evaluation Window of evaluation defaults to response having most duration in analysis spot 24

25 Establishing Window of Evaluation 12 Seconds 20 Seconds Default Window of Evaluation 25

26 RESPIRATORY WAVEFORM Evaluation Procedures Time for defaulted window of evaluation is from response onset to response end 26

27 RESPIRATORY WAVEFORM Evaluation Procedures Equivalent window of evaluation used for all other comparative responses in same analysis spot Variable window for each analysis spot 27

28 RESPIRATION LINE LENGTH In RLL procedure, when data is visually stretched, shorter line length signifies more intense or significant response and will be assigned numerical value. 28

29 RESPIRATORY WAVEFORM SCORING EXERCISE 29

30 RESPIRATORY WAVEFORM Score C1 Against R1 & R2 Score = +1 Score = +1 30

31 RESIRATORY WAVEFORM Score C1 Against R1 & R2 Score = -1 Score = -1 31

32 RESPIRATORY WAVEFORM Score C2 against R1 Score = -1 32

33 RESPIRATORY WAVEFORM Score C1 against R1 Score = -1 33

34 RESPIRATORY WAVEFORM One non-rll feature remains: Temporary increase in baseline 34

35 RESPIRATORY WAVEFORM Feature 6: Temporary Increase in Baseline l l - 35

36 TEMPORARY INCREASE IN BASELINE Value = +1 36

37 RESPIRATORY WAVEFORM Evaluation Procedures If one comparative response in analysis spot is RLL and other is non-rll, RLL response always gets value RLL features in analysis spot always take precedent over non-rll feature in same analysis spot 37

38 RESPIRATORY WAVEFORM Score C4 Against R5 RLL Non-RLL Value = +1 38

39 Respiratory Waveform Non-RLL Evaluation Procedures In scoring non-rll responses, most significant response will get assigned value. Significance is generally determined by the duration of the physiological change 39

40 Respiratory Waveform Score C4 Against R5? 11 Seconds 15 Seconds Value = -1 40

41 TEMPORARY INCREASE IN BASELINE Value = +1 41

42 Respiratory Waveform Non-RLL Diagnostic Feature Temporary Increase in Baseline Could easily become RLL feature if suppression occurs with baseline change If so, RLL scoring procedures apply 42

43 Temporary Increase in Baseline & Decrease in Amplitude 43

44 RESPIRATORY WAVEFORM Other Considerations May see exaggerated respiratory cycle in/around answer cycle May be exhibited many forms One cycle of something is nothing principle 44

45 RESPIRATORY WAVEFORM One Cycle of Something Is Nothing 45

46 RESPIRATORY WAVEFORM Other Considerations Respiratory channel is often called effector What occurs in respiratory channel has tendency to influence other channels Artifact in respiratory channel may effect ability to evaluate EDA and cardiovascular channels 46

47 ELECTRODERMAL CHANNNEL 47

48 ELECTRODERMAL WAVEFORM Two types of tracings are skin resistance (SR) and skin conductance (SC). The electrodermal (EDA) waveform consists of a relatively horizontal tracing indicative of the level of the electrical resistance/ conductance in the skin due to skin hydration. No stimulus applied 48

49 ELECTRODERMAL WAVEFORM Response Onset Window 49

50 ELECTRODERMAL WAVEFORM One primary diagnostic feature Amplitude Two Secondary diagnostic features Complexity Duration 50

51 ELECTRODERMAL WAVEFORM Primary Diagnostic Feature: Amplitude Peak Rise Recovery l l - l l - 51

52 ELECTRODERMAL WAVEFORM Evaluation Considerations Primary feature: Amplitude Equal amplitude is assigned zero (0) Visually discernable difference gets value of +/-1. 52

53 ELECTRODERMAL WAVEFORM You Make the Call l l - C Score = +1 l l - R 53

54 ELECTRODERMAL WAVEFORM Secondary Feature 1: Complex Response l l - 54

55 ELECTRODERMAL WAVEFORM Evaluation Considerations Complexity Dissimilar responses (simple v complex) Equal levels of amplitude Complexity may be assigned value 55

56 ELECTRODERMAL WAVEFORM Evaluation Considerations Simple v. Complex Response C Score = -1 R 56

57 ELECTRODERMAL WAVEFORM Secondary Feature 2: Response Duration l l - C Score = +1 l l - R 57

58 ELECTRODERMAL WAVEFORM EDA Duration Considerations Response duration is considered in Similar responses only Equal/equivalent levels of amplitude More duration may be assigned value 58

59 ELECTRODERMAL WAVEFORM Applying Duration Score = -1 c R Score = +1 c R 59

60 ELECTRODERMAL WAVEFORM Response Duration Score = -1 c 60 R

61 CARDIOVASCULAR SYSTEM 61

62 CARDIOVASCULAR WAVEFORM The contraction and relaxation of the heart causes the polygraph instrument to record the systolic stroke, diastolic stroke, and the dicrotic notch, which appears during the diastolic stroke. 62

63 CARDIOVASCULAR WAVEFORM SYSTOLIC STROKE DIASTOLIC STROKE DICROTIC NOTCH 63

64 CARDIOVASCULAR WAVEFORM Response Onset Window 64

65 CARDIOVASCULAR WAVEFORM Diagnostic Features Primary Scoring Feature Baseline arousal (Phasic response) 65

66 CARDIOVASCULAR WAVEFORM Primary Diagnostic Feature Phasic Response - Short-term change in physiological activity following stimulus presentation. Typically, this response has a relatively rapid onset and may return to the pre-stimulus baseline or establish a new baseline within a period characteristic of the response system. 66

67 CARDIOVASCULAR WAVEFORM Evaluation Features Phasic Responses l l - l l - 67

68 CARDIOVASCULAR WAVEFORM Evaluation Considerations Baseline arousal (phasic response) Primary feature More arousal gets value How do I know which response has more arousal? Any visually discernible difference 68

69 Value = +1 69

70 CARDIOVASCULAR WAVEFORM Two secondary diagnostic features Duration Decrease in Rate 70

71 CARDIOVASCULAR WAVEFORM Evaluation Features Determining Response Duration l l - l l - 71

72 CARDIOVASCULAR WAVEFORM Secondary Evaluation Considerations Impact of duration on the CV waveform Equal/equivalent levels of baseline arousal More duration may be assigned value 72

73 CARDIOVASCULAR WAVEFORM Secondary Evaluation Considerations Duration as a diagnostic feature Value = -1 73

74 CARDIOVASCULAR WAVEFORM Evaluation Features Decrease in Rate l l - 74

75 CARDIOVASCULAR WAVEFORM Secondary Evaluation Considerations Impact of decrease in rate on the CV waveform Considered if baseline arousal does not exist Response exhibiting most amount of duration or degree of change may be assigned value 75

76 CARDIOVASCULAR WAVEFORM Secondary Evaluation Considerations Decrease in rate as a diagnostic feature Value = -1 76

77 How to Score a Polygraph Chart This would be easy right? 77

78 CARDIOVASCULAR WAVEFORM QUESTIONS? 78

79 SEVEN-POSITION NUMERICAL EVALUATION SCALE Oct

80 RESPIRATORY SYSTEM 80

81 RESPIRATORY WAVEFORM 7-Position Scale Respiratory tracing Subtle (+1/-1) Obvious (+2/-2) Dramatic (+3/-3) 81

82 RESPIRATORY WAVEFORM 7-Position Scale Many times, a +/-2 or +/-3 value may be difficult to assign consistently unless similar respiratory attributes are exhibited or the comparative response is much more significant. 82

83 RESPIRATORY WAVEFORM 7-Position Scale It is anticipated that most respiratory values will remain in the 0 or +/- 1 category - even in the 7-position scale Occasionally, an examiner may find sufficient respiratory data to assign a value of +/- 2 Very rarely will an examiner assign values of +/- 3 83

84 ELECTRODERMAL CHANNNEL 84

85 ELECTRODERMAL WAVEFORM 7-Position Scale EDA tracing is generally most responsive. Ratio of response method is used to assign values. Unit of measurement is generally vertical chart division at 1/4 vertical grid setting. Assigned values are based on ratio scale: RATIO SCORE 4:1 +/- 3 3:1 +/- 2 2:1 +/- 1 1:1 0 85

86 ELECTRODERMAL WAVEFORM 7-Position Scale Exception to Ratio Scoring Method: Bigger is Better Principle for initial +/-1 After 2:1 ratio is reached, bigger is better principle no longer applies 86

87 ELECTRODERMAL WAVEFORM 7-Position Scale Complexity and duration may be assigned value of +/-1 only Once 2:1 ratio is reached, complexity and duration are not considered 87

88 Score EDA at C1 Against R1 & R2 2:1 Ratio 3:1 Ratio Score = -1 Score = -2 88

89 ELECTRODERMAL WAVEFORM Score EDA at C1 Against R1 & R2 4:1 Ratio B/B Score = -3 Score = -1 89

90 CARDIOVASCULAR SYSTEM 90

91 CARDIOVASCULAR WAVEFORM 7-Position Scale Baseline arousal (phasic response) is the only primary diagnostic feature Magnitude of comparative response is utilized to assign values 91

92 CARDIOVASCULAR WAVEFORM 7-Position Scale For a value of +/-1, response must be visually larger but less than twice the degree of baseline arousal than its comparative response. For +/-2, response must have twice but less than three times the degree of baseline arousal than its comparative response 92

93 CARDIOVASCULAR WAVEFORM 7-Position Scale For +/-3, response must have three times the degree of baseline arousal or more than its comparative response. 93

94 Cardiovascular Tracing - Score C1 Against R1 & R2 Score = -2 Score = -3 94

95 CARDIOVASCULAR WAVEFORM 7-Position Scale Comparative CV responses differentiated by less than one standard chart division are not assigned values higher than +/-1. 95

96 Cardiovascular Tracing - Response Differentiated By Less Than One Chart Division Score = -1 96

97 CARDIOVASCULAR WAVEFORM 7-Position Scale Other Considerations Secondary features of duration and decrease in rate may be assigned values of +/-1 only 97

98 QUESTIONS THANK YOU! 98

Application note Scoring GSR during stressful tasks: This application note will describe one method to automatically score GSR responses.

Application note Scoring GSR during stressful tasks: This application note will describe one method to automatically score GSR responses. For these expirments, the subject engaged in stressful tasks followed