Statistical Process Control Charts

I’ve had this idea for a while now – create a blog post and video tutorial discussing what Statistical Process Control is and how to use different Control Chart “tests” in Tableau.

I’ve spent a significant portion of my professional career in business process improvement and always like it when I can integrate techniques learned from a discipline derived from industrial engineering and apply it in a broader sense.

It also gives me a great chance to brush up on my knowledge and learn how to order my thoughts for presenting to a wide audience.  And let’s not forget: an opportunity to showcase data visualization and Tableau as the delivery mechanism of these insights to my end users.

So why Statistical Process Control?  Well it’s a great way to use the data you have and apply different tests to start early detection.  Several of the rules out there are aimed at finding “out-of-control,” non-normal, or repetitive parts within a stream of data.  Different rules have been developed based on how we might be able to detect them.

The video tutorial above goes through the first 3 Western Electric rules.  Full details on Western Electric via Wikipedia: here.

Rule 1: Very basic, uses the principle of a bell curve to put a spotlight on points that are above or below the Upper Control Limit (UCL) or Lower Control Limit (LCL) also known as +/- 3 standard deviations from the mean.  These are essentially outlier data points that don’t fall within our typical span of 99.7%.

Rule 2: Takes into consideration surrounding observations.  Looking at 3 consecutive observations are 2 out of 3 above or below the 2 SD mark from the average.  In this rule the observations must be on the same side of the average line when beyond 2 SD.  Since we’re at 95% at 2 SD, having 2 out of 3 in a set in that range could signal an issue.

Rule 3: Starts to consider even more data points within a collection of observations.  In this scenario we’re now looking for 4 out of 5 observations +/- 1 SD from the average.  Again, we’re retaining the positioning above/below the average line throughout the 5 points.  This one really shows the emergence of a trend.

I applied the first 3 rules to my own calorie data to see detect any potential issues.  It’s very interesting to see the results.  For my own particular data set, Rule 3 was of significant value.  Having it in line as the new daily data funnels in could prevent me from going on a “streak” of either over or under consuming.

 

Interact with the full version on my Tableau Public profile here.

#data16 Data Dump

Last night was our monthly Phoenix Tableau User Group (PHXTUG) meeting and as part of the post-excitement of Tableau’s 2016 conference we took some time to go through their strategy and some upcoming features.

Full video is available here:

Interested in reusing the slides? Find the deck here:

Tableau Conference 2016 – full prep details

Earlier in the week I wrote a blog post promising to share with you a slide deck put together that walks through what you should prepare yourself for with regards to the Tableau Conference in Austin, TX.

I’m happy to share with you not only the slide deck, but also a video of me presenting this information to the Phoenix Tableau User Group.  This was originally recorded live via Periscope and broadcast on social media.  I’ve saved the recording, cut it down a little, and packaged it on YouTube.  The video is completely raw – true to life video taken on my iPhone 7 Plus.

In tandem I uploaded the slide deck to SlideShare connected to my LinkedIn profile.  Check it out if you get a chance: