Trend Control Charts and Global Warming

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Thanks so much for reading our publication. We hope you find it informative and useful. Happy charting and may the data always support your position.


Dr. Bill McNeese
BPI Consulting, LLC

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Comments (6)

  • Nuno CostaJanuary 31, 2016 Reply

    You deserve my Congratulations for your (pedagogical) work.I suggest you illustrate this and other examples with your software. You may also provide a trial/student version. If so, I can use it, and promote your software, in my classes.Best regards

    • billJanuary 31, 2016 Reply

      Thanks for your comment.   All the charts in our publications are made using the SPC for Excel software.  And we do have free 20-day demo of the software here:/spc-software/demo
      We do a studenet version that can be rented for 6 monhts.  Please contact me if you interested.


  • Stanley AlekmanJuly 18, 2017 Reply

    This sentence, “R-squared for this regression is 82.37%, which means that 82.37% of the variation in global temperature deviation can be explained by the increasing year number“, I suggest is better stated as,” …82.37% of the variation in gobal temperature deviation is accounted for by the increasing year number.”Isn’t R-squared an accounting? Or are accounting and explaining synonyms?

    • billJuly 18, 2017 Reply

      I think, in this case, they are synonyms.  But I like your sentence better.  

      • AnonymousMay 25, 2019 Reply

        Hello,i am trying to create a Trend Control chart and was using your above example to replicate the process. I am new to control chart and was hoping if someone could explain how the Upper and lower limit was calculated for the above trend control chart.As stated above, the UCL is calculated using UCLx = b + mt + 2.66 = -3211.3 + 1.631(Year) + 2.66(10) (here,y-intercept has a value of -3211.3, given the y-intercept has such a low value does that not make the UCLx =3301.509 for 2015?? if the t = 39 (3211.3+1.631*(39)+2.66*(10)) Could you also explain how the R for the above example is 10.your response will be much appreicated.

        • billMay 25, 2019 Reply

          The SPC for Excel software, when calculating a trend, assumes the x values are 1, 2, 3, 4, etc.  Not the actual values used (in this exmaple the years).  So the equation will be different since I used excel's regression to use the acutal  year number and not 1, 2, 3, etc.).  Probably need to change that.   Rbar is 10.  It is the average range for the moving ranges between consecutive points.

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