F1 From Counts

Grid A Precision and Recall

Read precision and recall side labels for grid A.

highlighted = computed this step

Grid A precision

Precision uses TP over TP plus FP: 2 over 3.

precisionA=23\text{precision}_A={2\over3}
F1 Score ExactlyExact F1 fractions from two confusion grids.two confusion grids with exact F1 fractionsgrid Agrid A confusion gridactualpred Ppred NPTP=2FN=1NFP=1TN=1precision and recall side labelsratefractionprecision TP/(TP+FP)2/3 = 2/3recall TP/(TP+FN)2/3 = 2/3F1 denominator blocks2TP=4FP=1FN=12TP+FP+FN=6F1=4/6 = 2/3grid Bgrid B confusion gridactualpred Ppred NPTP=1FN=2NFP=0TN=2precision and recall side labelsratefractionprecision TP/(TP+FP)1/1 = 1recall TP/(TP+FN)1/3 = 1/3F1 denominator blocks2TP=2FP=0FN=22TP+FP+FN=4F1=2/4 = 1/2F1 is computed from displayed counts; denominator is 2TP plus FP plus FNdoes not claim: NOT best metric; NOT future performanceNOT accuracy; NOT calibration; NOT fairness; NOT safetyNOT generalization; NOT probability truth

Grid A recall

Recall uses TP over TP plus FN: 2 over 3.

recallA=23\text{recall}_A={2\over3}
F1 Score ExactlyExact F1 fractions from two confusion grids.two confusion grids with exact F1 fractionsgrid Agrid A confusion gridactualpred Ppred NPTP=2FN=1NFP=1TN=1precision and recall side labelsratefractionprecision TP/(TP+FP)2/3 = 2/3recall TP/(TP+FN)2/3 = 2/3F1 denominator blocks2TP=4FP=1FN=12TP+FP+FN=6F1=4/6 = 2/3grid Bgrid B confusion gridactualpred Ppred NPTP=1FN=2NFP=0TN=2precision and recall side labelsratefractionprecision TP/(TP+FP)1/1 = 1recall TP/(TP+FN)1/3 = 1/3F1 denominator blocks2TP=2FP=0FN=22TP+FP+FN=4F1=2/4 = 1/2F1 is computed from displayed counts; denominator is 2TP plus FP plus FNdoes not claim: NOT best metric; NOT future performanceNOT accuracy; NOT calibration; NOT fairness; NOT safetyNOT generalization; NOT probability truth

The side labels match

For grid A, both side labels show 2 over 3.

precisionA=recallA=23\text{precision}_A=\text{recall}_A={2\over3}
F1 Score ExactlyExact F1 fractions from two confusion grids.two confusion grids with exact F1 fractionsgrid Agrid A confusion gridactualpred Ppred NPTP=2FN=1NFP=1TN=1precision and recall side labelsratefractionprecision TP/(TP+FP)2/3 = 2/3recall TP/(TP+FN)2/3 = 2/3F1 denominator blocks2TP=4FP=1FN=12TP+FP+FN=6F1=4/6 = 2/3grid Bgrid B confusion gridactualpred Ppred NPTP=1FN=2NFP=0TN=2precision and recall side labelsratefractionprecision TP/(TP+FP)1/1 = 1recall TP/(TP+FN)1/3 = 1/3F1 denominator blocks2TP=2FP=0FN=22TP+FP+FN=4F1=2/4 = 1/2F1 is computed from displayed counts; denominator is 2TP plus FP plus FNdoes not claim: NOT best metric; NOT future performanceNOT accuracy; NOT calibration; NOT fairness; NOT safetyNOT generalization; NOT probability truth