NOAA / Space Weather Prediction Center

K6 Warning Contingency Table


This 2x2 contingency table summarizes the joint distribution of K6 short-term warnings during the period 1999 (when the warning product was first introduced) through 2013. The "Correct Null" value in the table represents the number of 3-hour geomagnetic intervals in the four year period for which no warning was issued and no K6 activity occurred. The summary statistics derived from the contingency table include the Bias (values less than 1 indicate fewer warnings issued than events observed), Heidke skill score (a corrected skill score that accounts for hits due to chance), Critical Success Index (also called the Threat Score), Probability of Detection (POD), and the False Alarm Ratio (FAR). Detailed definitions of these metrics are in the Verification Glossary.

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