MEPX
Chapter 1 of 10All chapters
  1. 1What is one row
  2. 2Rates and denominators
  3. 3Beyond the average
  4. 4Compared with what
  5. 5Aggregation traps
  6. 6Noise and significance
  7. 7Metrics and proxies
  8. 8Missing data
  9. 9Reading forecasts
  10. 10A reading routine

Chapter 1 of 10

What is one row

Start at the bottom.

The unit of observation

Before reading any total, establish what a single record represents: one person, one visit, one order, one order line. Aggregates are meaningless until that is clear.

  • Counting orders and counting customers give different answers.
  • Duplicates silently double the weight of whatever they duplicate.

Coverage

Ask what period, what population and what filters produced this table. Excluded rows shape every number in it and are rarely mentioned on the dashboard.