Table 1.
Features used in PD classifier, ranked by discriminative weight and scored with respect to the top-ranked feature: TimeBetweenRepeatQueries. Features are computed over all queries for each searcher. Features from the Motor class are first computed for each query instance and then averaged across all query instances for that searcher
| Feature name | Class | Brief description | Weight |
|---|---|---|---|
| TimeBetweenRepeatQueries | Repetition | AVG time between repeat queries | 1.000000 |
| FractionOfQueriesAreRepeats | Repetition | % of all queries that are repeat queries | 0.971182 |
| NumberOfTremorEvents | Motor | # of tremor eventsa | 0.715004 |
| AverageTremorFrequency | Motor | AVG tremor frequency in hertz (# of oscillations/time) | 0.595772 |
| FractionOfQueriesHaveSymptoms | Symptom | % of all queries with 1+ symptoms | 0.457336 |
| AgeIs50To85 | Risk Factors | Inferred searcher age is 50–85 years | 0.432355 |
| FractionOfClicksAreRepeats | Repetition | % of result clicks that are repeat clicks on same result | 0.341164 |
| FractionOfQueriesHaveRiskFactors | Risk Factors | % of all queries with 1+ risk factors | 0.329801 |
| GenderIsFemale | Risk Factors | Inferred gender is female | 0.313425 |
| TotalTimeCursorMoving | Motor | Total time mouse cursor is actively moving | 0.297699 |
| NumberOfScrollEvents | Motor | # of scroll events | 0.259432 |
| NumberOfScrollEventsDownward | Motor | # of scroll events downward | 0.256692 |
| AverageScrolVelocity | Motor | AVG scrolling velocity | 0.249454 |
| MinimumCursorYCoordinate | Motor | MIN y-coordinate of mouse cursor (top of page y is 0) | 0.247770 |
| FractionOfCursorTransitionsAreDirectionChanges | Motor | % of mouse cursor transitions with direction changesb | 0.243873 |
| AverageCursorAcceleration | Motor | AVG acceleration of mouse cursor | 0.239814 |
| NumberOfHyperlinkClicks | Motor | # of hyperlink clicks | 0.239568 |
| AverageCursorVelocity | Motor | AVG velocity of mouse cursor | 0.232418 |
| NumberOfCursorTransitionsAreDirectedUpward | Motor | # of transitions directed upward | 0.232311 |
| TotalDistanceScrolled | Motor | Total distance scrolled | 0.215000 |
| AverageCursorXCoordinate | Motor | AVG x-coordinate of mouse cursor (left of page x is 0) | 0.214955 |
| FractionCursorTimeInWhitespace | Motor | % of time mouse cursor in whitespacec | 0.211925 |
| MaximumDeviationInPreclickCursorTrail | Motor | MAX deviation in pre-click mouse cursor traild | 0.210185 |
| AveragePreclickCursorVelocity | Motor | AVG velocity of mouse cursor before click | 0.208572 |
| TotalScrollingTime | Motor | Total time spent scrolling | 0.207520 |
| AverageCursorJounce | Motor | AVG jounce of mouse cursor | 0.206460 |
| MinimumCursorXCoordinate | Motor | MIN x-coordinate of mouse cursor | 0.199193 |
| MaximumCursorVelocity | Motor | MAX mouse cursor velocity | 0.196639 |
| NumberOfCursorTransitions | Motor | # of mouse cursor transitions between logged points | 0.192631 |
| GenderIsMale | Risk Factors | Inferred gender is male | 0.191614 |
| AverageCursorVelocity | Motor | AVG velocity of mouse cursor | 0.190826 |
| CursorExhibitsReadingBehavior | Motor | Cursor shows evidence of reading behavior21 | 0.190713 |
| FractionCursorMoveTimeHaveTremors | Motor | % of mouse cursor move time having tremor events | 0.188127 |
| AverageCursorYCoordinate | Motor | AVG y-coordinate of mouse cursor | 0.171520 |
| AverageCursorJerk | Motor | AVG jerk of mouse cursor | 0.168440 |
| NumberOfTransitionsDirectedRightward | Motor | # of mouse cursor transitions directed rightward | 0.157965 |
| TotalNumberOfClicks | Motor | # of mouse clicks, inc. non-hyperlink (in whitespace) | 0.153249 |
| AverageAccelerationOfCursor | Motor | AVG acceleration of mouse cursor | 0.150714 |
| AgeIs35To49 | Risk Factors | Inferred searcher age is 35–49 years | 0.145166 |
| NumberOfNonHyperlinkClicks | Motor | # of non-hyperlink mouse clicks | 0.132365 |
| MaximumCursorYCoordinate | Motor | MAX y-coordinate of mouse cursor | 0.127897 |
| NumberOfCursorEvents | Motor | # of mouse cursor events | 0.126026 |
| NumberOfScrollEventsUpward | Motor | # of upward scroll events | 0.117682 |
| TotalCursorDistanceTraveled | Motor | Total distance traveled by mouse cursor | 0.111703 |
| AverageCursorPreclickOverrunDistance | Risk Factors | AVG pre-click mouse cursor link overrun distancee | 0.110122 |
| AverageCursorPreclickDeviation | Motor | AVG deviation in pre-click mouse cursor trail | 0.106043 |
| NumberOfCursorTransitionsDownward | Motor | # of mouse cursor transitions directed downward | 0.104645 |
| MaximumCursorJerk | Motor | MAX jerk of mouse cursor | 0.098519 |
| NumberOfCursorLoops | Motor | # of 360° loops in mouse cursor movementsf | 0.094700 |
| FractionOfTimeWithCursorInWhitespace | Motor | % of time spent with mouse cursor in whitespace | 0.092794 |
| MaximumCursorYCoordinate | Motor | MAX y-coordinate of mouse cursor | 0.081183 |
| NumberOfCursorTransitionsLeft | Motor | # of mouse cursor transitions directed left | 0.074749 |
| MaximumCursorJounce | Motor | MAX jounce of mouse cursor | 0.072211 |
| AgeIs25To34 | Risk Factors | Inferred searcher age is 25–34 years | 0.069420 |
| NumberOfCursorDirectionChanges | Motor | # of mouse cursor direction changes | 0.068290 |
| FractionQueriesWithRepeatQueryClick | Repetition | % of queries with repeat query-result click pair | 0.045272 |
| MaximumCursorPreclickVelocity | Motor | MAX velocity of pre-click mouse cursor trail | 0.035155 |
a Tremor events are defined as horizontal or vertical oscillations in the position of the mouse cursor, with a mouse cursor movement of no more than 20 pixels in either direction
b Transitions between logged cursor position data points where a change in mouse cursor direction is noted (e.g., moving the mouse cursor leftward then moving the mouse cursor rightward)
c Fraction of total time spent on the search engine result page where the mouse cursor is parked over whitespace (i.e. regions of the result page where there are no elements)
d Average residuals in a line of best fit for the five cursor position data points (i.e. the cursor trail) logged before a hyperlink click
e Total distance traveled (in pixels) by mouse cursor pre-click after initial pass over the target hyperlink
f Number of 360-degree loops in the mouse cursor trails, where a loop is defined as a sequence of direction changes resulting in a circular motion of the mouse cursor (e.g., move right, move down, move left, move up)