1 Reply Latest reply on Oct 30, 2017 8:17 AM by patrick.byrne.0

    Combining Metrics Calculated from branches with different degrees of aggregation.

    James Clark

      I'm having a problem combining two seperate calculations despite them both seemingly working fine alone.

      Here is our DB table structure.

      The learning session is the level of aggregation I ultimately report on.

      I want to see what the average Quiz level (a function of question results stored in either 'assessment_v2...' or 'teacher_selection'....) was for each Tutor ( a unique user ID stored in learning sessions). This works fine.

      I also want to know the percentage of the selected lesson that was completed. This is a count of the rows in 'achieved steps to success' with a stae > 2 divided by the total count, filtered by the condition: learning sessions: Lesson ID = feedback_granules: Lesson ID.

      This also works fine.

      The problem I have is when I want to see the average quiz results for only those learning sessions where the lesson was 100% completed.

      If I put in my calculated field of %complete into filters it work at the higher level of granulairty (e.g. only leaves tutors where all sessions have been completed not each) - If I drag the learning_sessions ID into detail, this solves the problem unless I want to display an average (it gives me the sum of all the averages) or export - it gives me a seperate cell for each learning session.

      Effectively both metrics are a single measure of learning session. Thus I really want tableau to calculate each seperately, 'store' them against Learning_sessions then let me manipulate them just as if they were each their own field of the Learning Sessions table.

      PS. It is difficult to attach example workbook as its educational data and thus contains confidential student information. I apprecaite this may make it harder to understand the problem, still any pointers would be really appreciated.

       

      Thanks

      James