Advanced trellis charts

1. Advanced trellis charts

Great job so far learning how to use Sigma to create trellis charts. In the last video we focused on trellising by a single field at a time, either a trellis row or a trellis column.

2. Analyzing hold durations across shifts

Let's go a step further and learn how and when we might want to trellis a chart by both a row and column field. Oakmark Bank's VP of Customer Service wants to understand the share of customers on hold for short, medium and long periods of time. They'd also like to understand whether hold times vary across morning, afternoon, evening and night shifts.

3. Analyzing hold durations across shifts

Using what we've learned about pie and donut charts, and trellising, we know that this can be framed as asking about proportions of a whole - or the share of customers experiencing different wait time ranges. We also hear the VP saying they want to see breakouts by time of day and by agent team. This is sounding like a great setup for trellised pie or donut charts. Let's try it out.

4. DEMO

To start, we have a single donut chart showing calls broken out by their hold duration. Most customers experience short or medium holds, with only 18% of callers experiencing what Oakmark considers a long hold time of 10 minutes or more. In the center, we see that the overall call center average for a hold time is 6.8 minutes.

5. DEMO

Let's first trellis this chart by time of day, to see whether the proportion of long holds is bigger at any time of day. Remember that trellis chart size can be changed in the format menu; choosing a "compact" trellis tile size fits the charts inside the element window.

6. DEMO

So far, it looks like hold lengths are relatively consistent throughout all times of the day, perhaps the night shift holds are a bit longer.

7. DEMO

Let's add [Agent Team] to the Trellis column section to see whether any one team experiences longer holds. Now that we see the breakout by team, a few insights emerge.

8. DEMO

Overall, hold times are relatively consistent, but it does appear that the Account Services night shift hold times are over a minute longer than the overall call center average. Perhaps this team could use some additional support.

9. DEMO

When you trellis by both a Row and Column in Sigma, the Trellis section of the chart's Format menu will now have submenus for formatting the row and column trellises differently. You can do things like turning on and off titles, labels and column and row borders to make your chart appear the way you want.

10. Let's practice!

Now it's your turn. In the next exercise, you'll help the VP of Customer Service build trellised charts to answer a similar question, this time about the amount of calls being escalated by call center agents.

Create Your Free Account

By continuing, you accept our Terms of Use, our Privacy Policy and that your data is stored in the USA.