Table 2.
Potential digital biomarkers of cognitive performance in Klondike Solitaire, divided into 5 categories.
| Digital biomarker | Description | Aggregation | Data type (range) |
|---|---|---|---|
| Result-based | |||
| Score | Final score of a game | value* | Integer (−∞, +∞) |
| Solved | Whether the game was completed or not | value* | Boolean |
| Game time | Total time spent playing a game, expressed in ms | value* | Integer (0, +∞) |
| Total moves | Total amount of moves made during the game | sum* | Integer (0, +∞) |
| Performance-based | |||
| Successful move | Number of successful moves | percentage* | Double (0.00–100.00%) |
| Erroneous move | Number of erroneous moves | percentage* | Double (0.00–100.00%) |
| Rank error | Number of rank errors | percentage* | Double (0.00–100.00%) |
| Suit error | Number of suit errors | percentage* | Double (0.00–100.00%) |
| King error | Number of kings misplaced | percentage | Double (0.00–100.00%) |
| Ace error | Number of aces misplaced | percentage | Double (0.00–100.00%) |
| Pile move | Number of pile moves | percentage* | Double (0.00–100.00%) |
| Cards moved | Number of cards selected for each move | average*, median, SD | Double (0.00, + ∞) |
| Beta error | Number of pile moves with moves remaining on the board | percentage* | Double (0.00–100.00%) |
| King beta error | Number of missed opportunities to place a king on an empty spot | percentage | Double (0.00–100.00%) |
| Ace beta error | Number of missed opportunities to place a king on the suit stacks | percentage | Double (0.00–100.00%) |
| Final beta error | Whether there was a missed move when quitting a game | value* | Boolean |
| Time-based | |||
| Think time | Time spent thinking of a move, expressed in ms | average*, SD*, min*, max, median | Integer (0, +∞) |
| Think time successful | Time spent thinking of a successful move, expressed in ms | average, median, SD, min, max | Integer (0, +∞) |
| Think time erroneous | Time spent thinking of an erroneous move, expressed in ms | average, median, SD, min, max | Integer (0, +∞) |
| Move time | Time spent moving card(s), expressed in ms | average*, SD*, min*, max, median | Integer (0, +∞) |
| Move time successful | Time spent moving card(s) for a successful move, expressed in ms | average, median, SD, min, max | Integer (0, +∞) |
| Move time erroneous | Time spent moving card(s) for an erroneous move, expressed in ms | average, median, SD, min, max | Integer (0, +∞) |
| Total time | Total time to make a move, expressed in ms | average*, SD*, min*, max, median | Integer (0, +∞) |
| Execution-based | |||
| Accuracy | Accuracy when selecting a card, defined by how close a card was touched to the center | average*, SD*, min*, max*, median | Double (0.00–100.00%) |
| Taps | Actuations on non-game or UI elements | sum* | Integer (0, +∞) |
| Auxiliary-based | |||
| Undo move | Amount of undos requested | percentage | Double (0.00–100.00%) |
| Hint move | Amount of hints requested | percentage | Double (0.00–100.00%) |
Remaining features used to train the models appear in bold type.
*
Remaining features after multicollinearity and zero value checks. SD, standard deviation; min, minimum; max, maximum.