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Calculational precedence: At the risk of being boring... - Visokio Forums
Calculational precedence: At the risk of being boring...
  • Guy_Cuthbert        Guy_Cuthbert October 5, 2010 6:24PM
    I know I have raised the subject of Group calculations vs Aggregation calculations before... although possibly not on the forums. I'm finding myself wrestling with them a lot at present, notably where different tables present the same numeric values with different total results, depending on the Aggregation going into the table. This is a case of a picture being worth a thousand words, so the attached image (01) highlights the problem.

    I understand why this happens, but I wanted to raise it as an issue again - because it prevents usage as shown in the attached image; how does the user know which (if either!) summary is correct?!

    The areas of the image to focus on are the "Stock Turn" and "Stock Payback" columns; these are calculated columns - the formulae are:
    • Stock Turn = Sold Qty / Current Stock Units (i.e. how many times, in a year, could I have sold the current stock given the sales rate over the past 12 months?)
    • Stock Payback = Current Stock Cost / Gross Profit (i.e. how many years does it take to generate a Gross Profit equal to the current value of stock?)

    The Pivot in the top left shows the number of items in a given Product Range - when selected, we have 2 Tables (top right, and bottom) which show a breakdown:
    • Top Right = full details i.e. every Item in the selected Range (77 items in the image)
    • Bottom = summarised by Product Group and Supplier, so that we can see whether we can discuss stock issues (longevity or excess value) with specific Suppliers

    The aggregation in the bottom table uses "Formula result" to calculate the [correct] values for each Supplier / Product Group. But in the Table view there is no way of using "Formula result" to derive a result... so we get different values in the two tables for the same underlying data.

    Omniscope does provide the option to "Calculate formula field results for group result values" (from the Formula menu, in the Table view), but whilst this yields the correct answer in the Top Right table, it doesn't affect the bottom table... and has the undesirable side effect of forcing all fields required by the formula to be displayed in the table (which, for complex multi-field formulae, isn't an option).

    I will post the result of selecting "Calculate formula field results for group result values" in a follow-up post (I can't add 2 images to this entry) to illustrate the problem.

    I appreciate that Grouping in tables is an architectural problem... but it means that it can be very dangerous to using multiple Table views on the same page; it's easy to confuse the user. More fundamental is that Omniscope is not presenting the *right* number in some cases; or at least it is very easy for the user to make that accusation, with some justification. Many people are used to reviewing summaries in tables - and they remain a useful way to look up a specific value - but such discrepancies in values present real problems when delivering client solutions.

    One for discussion, I think...
    Attachments
    group_omni_calcs_01.png 185K
    Atheon Analytics Ltd
    w: www.atheonanalytics.com
    e: guy.cuthbert@atheon.co.uk
    t: +44 8444 145501
    m: +44 7973 550528
    s: guycuthbert
  • 2 Comments
  • Guy_Cuthbert        Guy_Cuthbert October 5, 2010 6:26PM
    Follow-up to above... image (02) attached shows results of using "Calculate formula field results for group result values"
    Attachments
    group_omni_calcs_02.png 169K
    Atheon Analytics Ltd
    w: www.atheonanalytics.com
    e: guy.cuthbert@atheon.co.uk
    t: +44 8444 145501
    m: +44 7973 550528
    s: guycuthbert
  •     steve October 11, 2010 10:29AM
    Guy, please could we have a copy of this file. All we need are the columns in use.

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