Posted by: JC Gatlin | January 27, 2010

How to Collect Data for Problem Investigation

The purpose of data collection is to a.) prove the problem statement, and b.) determine the Point of Cause. The data is the cold hard facts that remove conjecture, speculation and any personal agenda from the problem solving methodology.

Step 1.
Prove the Problem Statement

Graphically present the details of problem statement. Consider using a graph, a chart or even a photograph.

In Graph 1 above, the PDCA group used a column graph that shows the number of homes behind schedule versus the total number of homes under construction between September and November 2009.

Step 2.
Break the data down for analysis

The next chart (or series of charts) should be analyzing the data, or start asking the 4 W’s and 1 H (What, Where, Why, When and How). Break the data down into bite sized chunks that tell a story – one graph at a time.

In Graph 2 above, the PDCA group asked “Where in the construction schedule was the delay occurring?” The group analyzed the 4 homes to find that 3 of the 4 were stalled at the electrical trim activity and displayed the data in a pie chart.

Next, in Graph 3 above, the PDCA group asked “Why was there a delay in electrical trim?” They used a Table to show that all 3 homes delayed at electric trim were waiting for backordered light fixtures.

Step 3.
Link critical data points in each chart

So that anyone reading the PDCA can follow the logic, circle critical data points on each chart. Then draw arrows leading from the point in the first chart to the point in the next chart.

Step 4
Identify the Point of Cause

The Point of Cause should be the critical data point of the last chart. Highlight and label the Point of Cause.

Step 5
Check for common missteps:

  • Is the group stuck at data collection? If so, the PDCA is suffering from Analysis Paralysis. Eliminate any tables, charts, graphs or information that does not support the problem statement. Then try to “tell a story” in four graphs or less.
  • Is the data collection hard to follow? If the data collection box looks like a play by play with John Madden, the PDCA probably suffers from information overload. Remove any information that does not directly support the problem statement and lead you to the Point of Cause. Yes – some of that data is very interesting. But irrelevant data will confuse and complicate the PDCA
  • Are there no graphs, charts or photos in the data collection – just alpha-numeric data (text and numbers)? It’s not wrong to do that, but the PDCA is losing its impact. Think outside the box. Use your imagination. A visual presentation of the data will convey information clearer, faster and easier.

© January 2010 Homebuilding Partners, Inc.   twitter-logo



  1. JC, I love the step by step description of problem solving.

    However, I think there is an important point missing that comes as the front door to data gathering. First, you must answer: what do I NOT understand that I must learn more about? If you don’t answer this, you may gather lots of data that isn’t really helping you move forward. The best case is that you wasted a little time gathering some data that didn’t help. The worse case is that you only think you understand the problem but you really don’t.

    We talk about this in The Hitchhiker’s Guide to Lean as the principle of “directly observe work as activities, connections, and flows.” That’s not the point of the principle, but it is about having a grasp of the current reality. The means may be direct eyeball observation, or less direct data (see today’s post on my blog on the abstraction of measures). But in either end of the spectrum, it is about learning. It’s about gathering insight and understanding that we didn’t have.

    That’s why the first question is: what don’t I understand that I must now learn about?



    • Great point. Thanks for the insight.

      Your point is well illustrated in a recent PDCA inwhich the cabinet installer is often unable to complete the installation due to backordered materials, and has to return to the jobsite once the materials arrive to finish the job. When they initiated the PDCA, the Construction Professional and cabinet installer first wrote each step in the process from the P.O. submitted by the builder to the cabinet installer, to the cabinet installer ordering the materials, to the materials arriving on the jobsite to the installer placing the cabinets. Before they could determine the problem statement, both parties had to first ask, “What’d don’t I understand that I must now learn about?” to fully understand the process on either side.

      Thanks again for the insight. I’m going to review that section of your book, The Hitchhiker’s Guide to Lean. It’s a great book.

      • Thanks. That’s a great example. The spirit that underlies that question is a focused curiosity, a deep desire to know what is really going on. That means suspending assumptions, especially those that involve blame.

  2. […] How to Collect Data for Problem Investigation dal blog Lean Homebuilding di J. C. Gatlin: Come raccogliere i dati per la investigazione del problema, dopo l’esame della dichiarazione e definizione del problema (traduzione automatica) […]

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