Improving data visualization: No more excel data tables!
Excel data tables are awful. Still, we often use them when presenting time-series charts because they are a convenient way to display the denominator for percentage or rate indicators. Why do we need the denominator? Two reasons. First, the denominator communicates the scale either of the intervention or the sample. Second, variation in the denominator might explain some of the variation seen in the displayed indicator.
For example, a time series may start with very high value, drop suddenly, and then climb back up to 100%. It looks at first like things were fine, then worsened, then slowly recovered, but closer examination of the denominator may reveal that the initial high value was based on data from only five patients, whereas the subsequent months were for thousands of patients. Including the denominator helps tell a different, more complete story.
So we include the denominator (and also the numerator). But Excel data tables aren’t a great solution:
- Improving data visualization: Using overlapping bar charts to present actual vs target data
- Improving data visualization: Where do I put all those annotations?