5 Replies Latest reply on Sep 15, 2016 11:43 AM by David Li

    Manual Forecasting

    Cody Smith

      Hi All


      I wanted help in creating a manual forecasting of the data I have. Currently I have data for 2015 ( all months) and from Jan to Aug in 2016. I wanted to have a parameter that increases or decreases the value from September to Decemeber 2016.

      For Sept 2016, I want to take the value of Sept 2015 and increase or decrease its value based on the parameter.


      For ex.

      The value in Sept 2015 is 400, and the percentage increase in Sept 2016 is 30%, So my value for Spet 2016 should be 400 + (400 *0.30) = 520.

        • 1. Re: Manual Forecasting
          David Li

          Hi Cody! Here's what I recommend:

          1. Create a parameter for the percentage increase and another couple of parameters that define the date range where this will take place. This will help in case you need to shift them later.
          2. Create a new calculated field that's something like this:

            IIF([Date] >= [Start Date] AND [Date] <= [End Date], [Hours]*(1+[Percentage Increase]), [Hours])

          EDIT: Fixed the calc and attached workbook.

          1 of 1 people found this helpful
          • 2. Re: Manual Forecasting
            Cody Smith



            Thanks for the post. I implemented the instructions as advised by you. But the Values for September 2016 is not changing.. I want to forecast the values for Sept 2016 onwards.

            • 3. Re: Manual Forecasting
              David Li

              Oh, I see now. I misunderstood your request originally. Try this table formula that uses LOOKUP() to find the month's value in the last year instead:

              IIF(MIN([Date]) >= [Start Date] AND MIN([Date]) <= [End Date], LOOKUP(SUM([Hours]), -12)*(1+[Percentage Increase]), SUM([Hours]))

              • 4. Re: Manual Forecasting
                Cody Smith



                Thanks a lot. Works fine.  Just one small question. I am currently working on the data source from oracle and the data is current. So my date values are only till September. I tried Domain Padding to fill up the remaining rows and its not working.


                Any Suggestions on that?


                Also, Is it possible to show 2 different colors in a single line graph ( For ex. Jan to Aug in Blue and the forecasted value from September to Dec in some other color).


                Thanks a Ton


                • 5. Re: Manual Forecasting
                  David Li

                  I'm glad it works!


                  You should ideally try to find some way to scaffold (pad) the additional months before the data gets into Tableau. I'm not very familiar with Oracle databases, so I don't know the best way to do this off the top of my head. If you have a DBA, it'd be a good idea to discuss with him/her. In situations I've encountered where I need scaffolding data, I usually ask the DBA to create a special table in the database for me to use.


                  It is indeed possible to show two different colors in a single line graph. We just create a calculated field like this and drop it on the color mark:

                  IIF(MIN(Date) > [Start Date], "Forecasted", "Measured")