Design of 2D Fitts’ law experiments: An odd thing about targets
Bibliographic record
Abstract
We explored the ISO 9241-411 multi-directional tapping (2D) test for evaluating computer pointing techniques. Based on Fitts' law, the test evenly distributes targets around a circular layout and requires the same movement distance between targets for all trials in a sequence. We demonstrate that this is only possible when using an odd number of targets. We reviewed 200 research papers using the 2D task and found that about a third of them use an even number of targets, and consequently report incorrect values for throughput, reinforcing the need to advertise this overlooked but relevant issue. Our findings imply that adhering to an odd number of targets and to the correct definition of movement distance ensures methodological consistency, leading to valid throughput values. Consequently, we argue for revisiting and updating the ISO 9241-411 standard to explicitly state that an odd number of targets is required for the 2D task.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".