1 Reply Latest reply on Mar 25, 2016 5:53 PM by Bill Lyons

    Calculate a forecast based on a calculated formula (not the forecast built in tool)

    tim tim

      January 2015: 100

      February 2015: 101

      March 2015: 102

      April 2015: 103

       

      My dataset shows the following 4 dates above. If I wanted to forecast to be +1 the month before. May 2015 as 104 and March 2015 as 105. Is this possible? (Extend this as far out as needed...lets say maybe year 2020)

       

      I don't want Tableau to tell me what the forecast line equation will be. I need it to calculate it on my own formula and preferably be able to change it. (Lets say I want to now do +2 the month before or *2 or /2 the month before.)

       

      Currently I have set reference lines at the desired months (Dec 2015 calculated field with value of 111) however this means a field and reference line for every month. I can't show the line growing towards December.

       

      Any help would be appreciated.

        • 1. Re: Calculate a forecast based on a calculated formula (not the forecast built in tool)
          Bill Lyons

          You can do this calculation external to Tableau, in your data source, and build a set of data with your forecast, and then visualize it in Tableau. We do this every day in SQL Server, calculating a forecast for income, including recent credit card decline rates, day of month for this time of year, etc. We put these values in a table with values for all days till the end of the month. We also include past days, and have columns for actuals as well as forecast, so we have different colored lines for actual and forecast.