Tracking Bus Arrivals with PBC Analyzer PRO

Lessons in How to Track Everyday Variation

The AIM for this short post is to share with you how you can use process behaviour charts to analyze everday variation, in this case the arrival times of my daughter’s schoolbus at the end of the day. I showed an earlier version of this analysis in my last newsletter, right before things became much more interesting.

As shown in the video above, I’ve accumulated an additional three weeks of arrivals which are recorded as +/- the target time, shown as the zero line on the chart.

The prior period, which started in mid-October has wild fluctuations that the driver attributed to last-minute route changes, additional kids to pick up and drop off, along with construction and heavy traffic. As you can see, it had a definite Rule 1 🔴 signal when the bus was 36m late!

Now, however, it appears that the route and number of kids on the bus has stabilized to the point where we’re getting Rule 2 🟠 signals that usually presage a change. Clicking to shift the limits at index 16 revealed a surprise: whereas before the arrival times were oscillating around a +7.38m mean, segmenting the chart in two to “shift the limits” reveals that the arrival times are moving around a mean of zero, the actual target. This is a big deal!

For weeks the driver has been frustrated with his management’s decisions and has fought them to bring stability back into his system: I have the proof that backs this up. Not only did he bring his performance closer to target, but he narrowed the band of variation to be +/- 14m vs. +43m/-15m.

You can try this analysis out yourself with the free version of PBC Analyzer PRO here, and paid-tier subscribers can refresh their sample data file by clicking the Download Sample File button and running the same analysis, and more besides using any Excel data file.

I plan on sharing this chart with the driver as a little gesture of validation for his efforts: he takes pride in his job, and has taken it personally when he can’t meet his schedule, all for things outside of his direct control. This will show his efforts haven’t been for naught and can be tangibly proven.