Attention Task Accuracy Calculator

Work out attention task accuracy instantly with clear inputs, formula shown and shareable results.

About Attention Task Accuracy Calculator

Signal detection theory separates sensitivity from bias. Sensitivity d prime is the difference between the z-transformed hit rate and false alarm rate: 84% hits against 12% false alarms gives d prime 2.17. Raw accuracy of 86% would conflate the two, hiding whether the participant is genuinely discriminating or simply cautious.

Formulas

Sensitivity

d' = z(hit rate) - z(false alarm rate)

Response bias

c = -0.5 x (z(hit rate) + z(false alarm rate))

Worked example

With the default values below, Attention Task Accuracy Calculator returns Sensitivity (d prime) of 2.1694. Change any input above and every figure here is recalculated in your browser.

Inputs used

Correct detectionsminimum 0: 42
Missed targetsminimum 0: 8
False alarmsminimum 0: 6
Correct rejectionsminimum 0: 44

Results

Sensitivity (d prime): 2.1694
Overall Accuracy: 86.00%
Hit Rate: 84.00%
Response Bias (Criterion c): 0.0903

Step by step

1Values used
2Sensitivity
3Response bias
4Sensitivity (d prime)= 2.1694
5Overall Accuracy= 86.00
6Hit Rate= 84.00
7Response Bias (Criterion c)= 0.0903

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Why not just report accuracy?

Because accuracy mixes discrimination with willingness to respond. Someone who says yes to everything scores well on hits and terribly on false alarms.

What does the criterion mean?

Negative values indicate a liberal bias towards responding yes, positive values a conservative bias. Zero is unbiased.