{"id":"forecast_backtest_summary","columns":[{"name":"metric_id","type":["string","null"]},{"name":"origin_count","type":["integer","null"]},{"name":"first_origin_period","type":["integer","null"]},{"name":"last_target_period","type":["integer","null"]},{"name":"mean_signed_error","type":["number","null"]},{"name":"mean_absolute_error","type":["number","null"]},{"name":"median_absolute_error","type":["number","null"]},{"name":"mean_absolute_percentage_error","type":["number","null"]},{"name":"median_absolute_percentage_error","type":["number","null"]},{"name":"mean_signed_percentage_error","type":["number","null"]},{"name":"overforecast_share","type":["number","null"]},{"name":"max_absolute_error","type":["number","null"]},{"name":"notes","type":["string","null"]}],"empty_values":"CSV empty fields and JSON null mean unavailable; an explicit zero is numeric zero.","source_reference":"Source URL plus page, row, column, or line fields where supplied. Financial columns keep their own budget stages."}