Reader Poll: Should the axis for bar charts always start at zero?

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It all began with my Excel Dashboard Tutorial – Making a dashboard with player statistics. I have used bar charts with axis whose minimum is not zero, to create a dramatic effect in the charts. See below:

excel-barchart-rule-breaking

Jon Peltier commented saying that,

Rule #1: Bar and column chart value axes should start at zero. Since the lengths of bars and columns represent their values, starting at a position other than zero will lead to a misleading display.

As always Jon raised an excellent point. I liked it so much that I wanted to get your opinions on this axis scaling issue.

What do I think about this visualization rule ?

First the positive points about the rule:

  • If you start axis at non-zero values, it gives a wrong impression about the data. In my example above you might end up thinking the top value is actually 10 times that of bottom value.
  • The rule helps easy interpretation of data, since everything starts at zero.


Now the negative points about the rule:

  • Not all data starts at zero (like the above with values ranging from 8000 to 12000). So when you create a bar chart for the data (why only bar charts, because they are easy to make and read) often you end up creating charts from which making out any analysis could be slightly difficult
  • Breaking this rule helps in creating dramatic effect on your charts, one of the reasons we use them. Often when you use data with narrow range, creating dramatic effect could be difficult. Axis adjustments can help (you may want to try logarithmic axis scale as well)

Finally, I think this rule can be broken as long as we have right data and make alternative arrangements (like adding data labels) to ensure correct interpretation. Since this is a standard people have come to expect, it is better to make it clear to your audience about the axis range.

What do you think about the charting rule: Bar and column chart value axes should start at zero.

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19 Responses to “How to Distribute Players Between Teams – Evenly”

  1. Roshan Thayyil says:

    An excellent solution, especially for large data sets.

    Another solution without using solver would be to assign the player with the highest score to Team 1, the 2nd to team 2, 3rd to team 3, 4th to team 3, 5th to team 2, 6th to team 1, 7th to team 1 and it continues. This method would end up with a Std Dev of 0.001247219. This works best with a distribution with lower Std Dev for the dataset.

    Full Disclosure: this is not my idea, remember reading something a few years ago. Think it may have been Ozgrid

    • Roshan Thayyil says:

      thinking back I now remember why I read about it. About 10 years back I had to distribute around 300 team members into 25-30 odd teams. Used this method based on their performance scores. I used the method I described to do this and the distribution was pretty fair.

      Solver would have saved me a ton of time though 🙂

  2. I think the issue with you first Solver approach was that you took the absolute value of the sum of team deviations (which should always be zero except for rounding) instead of the sum of the absolute values (which is a reasonable measure of how unbalanced the teams are).

  3. Here's another simple algorithm you could use: you start from the top (with players sorted from high to low), and at each step allocate the next player to whichever team has the smallest total so far. You can implement it dynamically with some formulas so it will update automatically when the data changes.

    If the scores were more widely distributed (so that this might end up with not all teams the same size), you could add a constraint to only pick among the teams which currently have fewest players at each step, or just stop adding to any team when it hits its quota.

    When I tried it on the sample, I got the three teams below, with a STDEV of 0.000942809 (i.e. about half of what Solver got to).

    Team 1: John, Hugo, Tom, Josh, Eric, Zane, Charles, Andrew
    Team 2: Barry, Michael, Kenny, Joe, Xavier, Patrick, Oliver, William
    Team 3: Henry, Steven, Ben, Frank, Kyle, Edward, Cameron, Lachlan

    Thanks for sharing!

    • Ishaan says:

      Hi,
      I was looking at all the solutions and this is closest to what I intended to do. I am dividing a bunch of players into 3 soccer teams. Players availability is also a factor while deciding the teams.
      So the steps the excel needs to do is as follows:
      1) In availability column if "yes" go to next
      2) Equally divide 'Goalkeepers', 'Strikers', 'Defenders' basis their quality
      So the end result gives each 3 teams a balance of players playing at different positions.
      Can this be done on Google spreadsheet with only availability as an input from the user and rest calculates by itself.
      Sorry for asking such a pointed question, but I have been struggling to find a solution for it for sometime now!

      • Robin says:

        Hi Ishaan,

        I am working on a similar problem at the moment, so I am wondering if you ever found a solution and if you are willing to share what you did.

  4. Konrad says:

    Hi everyone, this is a variation of the famous Knapsack Problem https://en.wikipedia.org/wiki/Knapsack_problem.

    I had to use a VBA implementation recently as part of a problem, where we ar trying to allocate teams of an organization into different locations (we are a large company with many different team). The goal was to optimally allocate teams to individual buildings without putting too many teams into one building and not splitting teams apart.
    As we had around 400 teams of different sizes, solver couldn't handle it anymore. Luckily there is a Knapsack algorithm implementation in VBA readily available on the internet :).

    I also went with a heuristic approach first!

  5. Joe Egan says:

    An interesting mathematical solution but what if Eric and Xavier can't stand each other or Patrick is best friends with Steven - the real life problems that effect "even" teams.

    • Hui... says:

      @Joe

      You can add more criteria like
      If Eric and Xavier can't stand each other
      =OR(AND(E15=1,E16=1),AND(F15=1,F16=1),AND(G15=1,G16=1))
      It must be False

      If Patrick is best friends with Steven
      =OR(AND(E5=1,E17=1),AND(F5=1,F17=1),AND(G5=1,G17=1))
      It must be True

      Note that the 2 formulas above are exactly the same
      except for the ranges
      One must be True = Friends
      One must be False = Not Friends

  6. Gustavo Sousa says:

    Nice post Hui!

    I download your workbook and just try to change in options the Precision Restriction from 10E-6 to 10-8 and the Convergence from 10E-4 to 10E-10. The process take almost the same time, but the results was great.

    The standard deviation I got was 0,000471.

    Team 1: John, Tom, Kenny, Frank, Eric, Xavier, Edward, Zane
    Team 2: Steven, Hugo, Ben, Joe, Josh, Oliver, Cameron, William
    Team 3: Barry, Henry, Michael, Kyle, Patrick, Charles, Andrew, Lachlan

  7. Charlie says:

    Great application of Solver! Thanks for the link!

  8. Chuck says:

    Great explanation. Well done... However, I tried with 6 teams of 4 players and solver never did finish.

  9. Akbar says:

    How about vba code for the same data set.
    I have 3 column A B C wherein A has text and B has number Wherein C is blank. And in C1 been the header C2 where I want the name to come evenly distributed the number which is in Column B.
    My Lastcolumn is 1000.

  10. HRMFT says:

    Sorry if I'm being slow here, but how is 'Team Score' calculated? I've gone through the explanation several times but it seems to just appear.

    • Hui... says:

      @Hrmft

      This process uses the Solver Excel addin

      Solver is effectively taking the model and trying different solutions until it gets a solution that meets all the criteria
      Then solver puts the solution into the cell and moves to the next cell

      So yes it appears to "just appear"

  11. Caroline says:

    Hi ! Thank you so much ! Works great 🙂

  12. Jim Cruse says:

    I cannot get the fourth Equation to work in my excel spreadsheet
    You have =($E$2:$G$25=0)+($E$2:$G$25=1)=1 as a SUMIF solution, I have, =($F$2:$H$13=0)+($F$2:$H$13=1)=1 as my solution but it does not work. The only thing I changed is the ranges. Any suggestions?
    Thank you.
    Jim

  13. Jim Cruse says:

    I cannot get the fourth Equation of TURE or FALSE statements to work in my excel spreadsheet You have =($E$2:$G$25=0)+($E$2:$G$25=1)=1 as a SUMIF solution, I have, =($F$2:$H$13=0)+($F$2:$H$13=1)=1 as my solution but it does not work. The only thing I changed is the ranges. Any suggestions?
    Sorry I left some of it out in the previous question,
    Thank you. Jim

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