In this comprehensive guide, we will explore everything you need to know about the FORECAST.ETS.STAT function in Excel. This function is a powerful tool for analyzing time series data and generating statistical values for forecasting. Whether you are a beginner or an advanced Excel user, this article will provide you with valuable insights, examples, tips, and tricks to help you master the FORECAST.ETS.STAT function.


The FORECAST.ETS.STAT function has the following syntax:

FORECAST.ETS.STAT(target_date, values, timeline, statistic_type, [seasonality], [data_completion], [aggregation])

Here is a breakdown of the arguments:

  1. target_date: The date for which you want to forecast the statistic.
  2. values: The range of historical data points used for the forecast.
  3. timeline: The range of dates or periods corresponding to the historical data points.
  4. statistic_type: A number from 1 to 8, representing the type of statistic you want to calculate. Each number corresponds to a specific statistic, as detailed below:
  1. Alpha (ETS Smoothing Constant)
  2. Beta (ETS Trend Smoothing Constant)
  3. Gamma (ETS Seasonality Smoothing Constant)
  4. MASE (Mean Absolute Scaled Error)
  5. MAE (Mean Absolute Error)
  6. RMSE (Root Mean Square Error)
  7. SMAPE (Symmetric Mean Absolute Percentage Error)
  8. ETS Algorithm (1 for additive, 2 for multiplicative)
  1. [seasonality] (optional): A number representing the length of the seasonal pattern. If omitted, Excel will automatically detect the seasonality.
  2. [data_completion] (optional): A number representing how to handle missing data points. 1 means to complete the data, and 0 means not to complete the data. If omitted, the default is 1.
  3. [aggregation] (optional): A number representing the method to aggregate data when multiple data points have the same time stamp. If omitted, the default is 0 (average).


Let’s explore some examples of how to use the FORECAST.ETS.STAT function in Excel:

Example 1: Basic Usage

Suppose you have monthly sales data for the past two years and want to forecast the Alpha (ETS Smoothing Constant) for the next month. You can use the following formula:

=FORECAST.ETS.STAT(“2023-01-01”, B2:B25, A2:A25, 1)

In this example, the target_date is “2023-01-01”, the values range is B2:B25, and the timeline range is A2:A25. The statistic_type is set to 1 for Alpha.

Example 2: Specifying Seasonality

If you know the seasonality of your data, you can specify it in the formula. For example, if your data has a quarterly seasonality, you can use the following formula:

=FORECAST.ETS.STAT(“2023-01-01”, B2:B25, A2:A25, 1, 3)

In this example, the seasonality is set to 3, representing a quarterly pattern.

Example 3: Handling Missing Data

If your data has missing values, you can choose how to handle them using the data_completion argument. To not complete the missing data, use the following formula:

=FORECAST.ETS.STAT(“2023-01-01”, B2:B25, A2:A25, 1, , 0)

In this example, the data_completion argument is set to 0, indicating that missing data points should not be completed.


Here are some tips and tricks to help you get the most out of the FORECAST.ETS.STAT function:

  1. Ensure that your timeline and values ranges have the same number of data points. Mismatched ranges can lead to errors or incorrect results.
  2. When using dates in the target_date argument, make sure they are formatted as dates in Excel. This will ensure accurate results.
  3. Experiment with different statistic types to gain a deeper understanding of your data and improve your forecasting accuracy.
  4. Use the optional arguments to fine-tune your forecasts and handle specific situations, such as known seasonality or missing data.

Common Mistakes When Using FORECAST.ETS.STAT

Here are some common mistakes to avoid when using the FORECAST.ETS.STAT function:

  1. Using an incorrect statistic_type value. Make sure to use a number between 1 and 8, as detailed in the syntax section.
  2. Not specifying the seasonality when it is known. This can lead to less accurate forecasts.
  3. Ignoring missing data points. If your data has gaps, consider using the data_completion argument to handle them appropriately.

Why Isn’t My FORECAST.ETS.STAT Working?

If your FORECAST.ETS.STAT function is not working, consider the following troubleshooting steps:

  1. Check your formula for syntax errors, such as missing or incorrect arguments.
  2. Ensure that your timeline and values ranges have the same number of data points.
  3. Verify that your target_date is formatted as a date in Excel.
  4. Review the optional arguments to make sure they are set correctly for your specific situation.

FORECAST.ETS.STAT: Related Formulae

Here are some related formulae that you may find useful when working with time series data and forecasting in Excel:

  1. FORECAST.ETS: This function calculates the forecasted value for a specified future date based on historical data.
  2. FORECAST.LINEAR: This function calculates a linear forecast for a specified future date based on historical data.
  3. TREND: This function calculates the linear trend of data points and can be used to extend the trend into the future.
  4. GROWTH: This function calculates the exponential growth of data points and can be used to extend the growth into the future.
  5. ETS.SEASONALITY: This function calculates the length of the seasonal pattern in the historical data.

By mastering the FORECAST.ETS.STAT function and related formulae, you can greatly enhance your ability to analyze time series data and generate accurate forecasts in Excel. We hope this comprehensive guide has provided you with valuable insights and practical examples to help you on your journey.


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