{
  "category": "Statistical functions",
  "display_name": "FORECAST.ETS",
  "entry_kind": "built_in_function",
  "eval_api": {
    "method": "POST",
    "url": "https://handbook.dnacalc.com/api/eval"
  },
  "function_id": "FUNC.FORECAST.ETS",
  "implementation_state": {
    "answer_bank": null,
    "detail": "Listed by Microsoft; no catalogue row yet.",
    "dnacalc_commit": "9e1884369a678158dd82d3d74188daf986995e87",
    "in_catalogue": false,
    "state": "refuses",
    "state_label": "Refuses or not implemented",
    "summary": "Not implemented",
    "workbook_corpus": null
  },
  "implementations": [],
  "json_url": "https://handbook.dnacalc.com/api/functions/FUNC.FORECAST.ETS.json",
  "name": "FORECAST.ETS",
  "notes": [],
  "schema": "efh.function-reference/v1",
  "section_order": [
    "what-it-does",
    "try-it",
    "quirks",
    "how-to-implement",
    "version-differences",
    "alternatives"
  ],
  "sections": {
    "alternatives": "\n- `FORECAST.LINEAR` for a straight-line forecast.\n- `TREND` and `GROWTH` for fitted series.\n- The Forecast Sheet command, which builds on the same family.\n\n\n",
    "how-to-implement": "\nNo implementation exists yet. It needs the AAA exponential smoothing fit, the detection of a constant timeline step, seasonality\ndetection, the data-completion and aggregation rules, and recorded Excel answers to fix the optimiser's stopping\nrules. Forecast values depend on those rules, so they must be measured and not assumed.\n\n\n",
    "quirks": "\n- `#NUM!`: the target precedes the end of the history, no constant step exists, or `seasonality` is invalid or above 8,760.\n- `#N/A`: `values` and `timeline` differ in size.\n- `#VALUE!`: Microsoft's timeline section lists this for duplicate timeline values, while its aggregation\n  section says duplicates are combined. The two statements conflict, and no reading is recorded here to settle it.\n\n\n",
    "sources": "\n- [FORECAST.ETS function](https://support.microsoft.com/en-us/excel/functions/forecast-ets-function)\n\n",
    "version-differences": "\nMicrosoft says these functions are not available in Excel for the web, iOS or Android. No Excel answers for this function are recorded here, so no comparison between Excel builds exists.\n\n\n",
    "what-it-does": "\n`FORECAST.ETS` predicts a future value from a timed series, using the AAA version of exponential smoothing.\n\n`FORECAST.ETS(target_date, values, timeline, [seasonality], [data_completion], [aggregation])`\n\n- **`target_date`** is the point to predict, a date or number after the end of the history.\n- **`values`** is the history.\n- **`timeline`** is the matching dates or numbers, with a constant nonzero step. It need not be sorted.\n- **`seasonality`** is 1 to detect the pattern (default), 0 for none, or a positive pattern length up to 8,760.\n- **`data_completion`** is 1 to fill missing points with the average of their neighbours (default), or 0 to treat\n  them as zeros. Up to 30% of points may be missing.\n- **`aggregation`** combines values sharing a timestamp: 0 AVERAGE (default), then SUM, COUNT, COUNTA, MIN, MAX and MEDIAN.\n\n\n"
  },
  "signature": {
    "display": "FORECAST.ETS(target_date, values, timeline, [seasonality], [data_completion], [aggregation])",
    "parameters": [
      {
        "description": null,
        "name": "target_date",
        "optional": false,
        "repeats": false
      },
      {
        "description": null,
        "name": "values",
        "optional": false,
        "repeats": false
      },
      {
        "description": null,
        "name": "timeline",
        "optional": false,
        "repeats": false
      },
      {
        "description": null,
        "name": "seasonality",
        "optional": true,
        "repeats": false
      },
      {
        "description": null,
        "name": "data_completion",
        "optional": true,
        "repeats": false
      },
      {
        "description": null,
        "name": "aggregation",
        "optional": true,
        "repeats": false
      }
    ],
    "trailing_repeats": false
  },
  "sources": {
    "metadata": {
      "admission": {
        "label": "not_implemented",
        "reason": "Listed by Microsoft; no catalogue row yet."
      },
      "arity": {
        "max": 6,
        "min": 3
      },
      "category": "Statistical functions",
      "classification": {},
      "descriptions": {
        "long": null,
        "short": "Future value by exponential triple smoothing",
        "short_source": "dna-calc-own"
      },
      "docs": {
        "english_description": null,
        "microsoft_url": "https://support.microsoft.com/en-us/excel/functions/forecast-ets-function"
      },
      "entry_kind": "built_in_function",
      "localized_family_names": null,
      "localized_names": [],
      "signature": {
        "display": "FORECAST.ETS(target_date, values, timeline, [seasonality], [data_completion], [aggregation])",
        "parameters": [
          {
            "description": null,
            "name": "target_date",
            "optional": false,
            "repeats": false
          },
          {
            "description": null,
            "name": "values",
            "optional": false,
            "repeats": false
          },
          {
            "description": null,
            "name": "timeline",
            "optional": false,
            "repeats": false
          },
          {
            "description": null,
            "name": "seasonality",
            "optional": true,
            "repeats": false
          },
          {
            "description": null,
            "name": "data_completion",
            "optional": true,
            "repeats": false
          },
          {
            "description": null,
            "name": "aggregation",
            "optional": true,
            "repeats": false
          }
        ],
        "trailing_repeats": false
      },
      "surface_name": "FORECAST.ETS",
      "version_marker": null,
      "xlcall": null
    },
    "microsoft": "https://support.microsoft.com/en-us/excel/functions/forecast-ets-function"
  },
  "try_it": {
    "formula": "=FORECAST.ETS(6,{1,2,3,4,5},{1,2,3,4,5})",
    "note": "The OneCalc preview has no answer for this function: see the state above.",
    "preview_status": "worksheet-error"
  },
  "url": "https://handbook.dnacalc.com/functions/FORECAST.ETS.html",
  "variants": [],
  "versions": []
}