What Weather Event Equitable Threat Score represents
Random hits are estimated from observed-event and forecast-event marginals divided by total cases.
Weather Event Equitable Threat Score begins with hits, misses, false alarms, correct negatives. Label the forecast system, initialization, lead time, valid period, observation source, event definition, sample, and aggregation before interpreting the output.
Building a matched sample
Use a complete 2×2 contingency table with one event threshold.
For Weather Event Equitable Threat Score, preserve location or grid, valid time, lead, variable, threshold, accumulation, units, observation latency, quality control, missing-case rule, spatial matching, and any interpolation or neighborhood method.
Interpreting Equitable threat score
The default table gives random hits 30 and ETS 0.25.
Compare Weather Event Equitable Threat Score only across samples with compatible event frequency, difficulty, domain, season, lead, observation source, weighting, and postprocessing. A lower raw error on an easier sample does not prove a better system.
Continue the Weather Event Equitable Threat Score evaluation with the related Weather Event Frequency Bias Calculator, retaining the identical matched sample and conventions.
Boundary and sanity checks
Total and adjusted denominators must be positive.
Change one Weather Event Equitable Threat Score input and predict the response. Test perfect forecasts, zero-error cases, all-event or no-event tables, probability endpoints, and denominators before accepting a score.
Where verification stops
ETS can be unstable for small samples and is still sensitive to base rate and sampling design.
Weather Event Equitable Threat Score describes the entered sample; it does not issue a forecast, establish operational skill, certify a model, select a warning threshold, or authorize weather-sensitive decisions.
Sampling uncertainty and sensitivity
Bootstrap or otherwise resample matched cases when uncertainty in Weather Event Equitable Threat Score matters. A displayed point score can change with a few rare events, observation revisions, spatial tolerance, or one extreme miss.
The Weather Event Equitable Threat Score calculator does not create confidence bounds unless that is its explicit formula. Dependence, serial correlation, multiple comparisons, and data snooping require separate treatment.
Continue the Weather Event Equitable Threat Score evaluation with the related Weather Ensemble Spread Calculator, retaining the identical matched sample and conventions.
Binary-event table conventions
Hits, misses, false alarms, and correct negatives must be mutually exclusive and exhaustive. Weather Event Equitable Threat Score denominators determine whether a statistic conditions on observations, forecasts, or all cases.
False alarm ratio is not false alarm rate. Accuracy can be dominated by correct negatives, while CSI ignores them. Skill scores add reference or chance assumptions that must travel with Weather Event Equitable Threat Score.
Probabilities and ordered categories
Probability verification requires a precise event and reliable outcome. Weather Event Equitable Threat Score probabilities enter as percentages but become 0–1 fractions inside squared scores.
Ranked probability scoring uses cumulative boundaries across ordered categories. Reordering categories or allowing probabilities not to sum to one changes the meaning of Weather Event Equitable Threat Score.
Audit trail and reproducibility
Save raw Weather Event Equitable Threat Score pairs or table cells, sample filters, formula version, unrounded score, rounded score, reference method, and quality flags. A reviewer should reproduce the result without guessing missing-case treatment.
When forecasts or observations are revised, create a dated Weather Event Equitable Threat Score version and preserve the earlier score. Do not silently replace a verification archive after products have been compared.
Formula, sign, and denominator
The relationship is ETS = (H − H_random) ÷ (H + M + FA − H_random). Weather Event Equitable Threat Score uses only displayed values and fetches no forecasts, observations, climatology, ensembles, or verification archives.
Keep forecast-minus-observed sign distinct from absolute error. For Weather Event Equitable Threat Score, document percent versus fraction, population versus sample denominator, contingency-table orientation, category order, weighting, and reference forecast.
Checked numerical example
For 40 hits, 10 misses, 20 false alarms, and 30 correct negatives, ETS is exactly 0.25.
Reset restores this Weather Event Equitable Threat Score example. Recalculate it independently, including probability conversion, table marginals, square roots, and threshold equality, before using another verification sample.
Frequent verification errors
Typical Weather Event Equitable Threat Score errors include mixing leads, verifying probabilities against mismatched thresholds, counting one case twice, treating missing outcomes as nonevents, or comparing skill scores with different references.
Reject impossible Weather Event Equitable Threat Score combinations instead of forcing an output. Keep counts integral in source data, probabilities bounded, category totals normalized, and denominators visible. Report sample size with every Weather Event Equitable Threat Score score. Also retain forecast initialization cycles, lead-time bins, duplicate-removal rules, observation latency, spatial tolerance, and whether cases were pooled before or after scoring. These choices can alter a result even when the same forecasts are present. Before publication, compare the metric with a simple baseline and at least one complementary score, then inspect individual largest-error or rare-event cases rather than relying on the aggregate alone. Archive the exact Weather Event Equitable Threat Score case list so later systems can be evaluated fairly.
Forecast verification questions
Does one score prove forecast quality?
No. Weather Event Equitable Threat Score needs sample size, uncertainty, stratification, and complementary metrics.
How should the answer be rounded?
Keep full precision inside Weather Event Equitable Threat Score, then round consistently with sample uncertainty and reporting practice.
When should I recalculate?
Recalculate Weather Event Equitable Threat Score when forecasts, observations, filters, event definitions, weights, or references change.
What does Weather Event Equitable Threat Score calculate?
Weather Event Equitable Threat Score calculates equitable threat score from the displayed forecast-verification inputs.