## March 20, 2004

### Simplify, simplify!

Today, I figured out how to simplify the explanation of the net-flow rate. It makes no real difference either in calculations or in the complexity of the spreadsheet, but it'll reduce the difficulty of explaining it to non-demographers.

Here's the gist: the increase in enrollment for grades x on up between any two points in time is equal to

- the number of those who enroll in grade x for the first time between those two points

**minus**

- those who graduate between the two points

**plus**

- those who enter for all other reasons (moving into an area, transferring from other schools, returning to school)

**minus**

- those who leave for all other reasons (moving away, transferring to other schools, dying, dropping out).

The last two terms can be collected as residual net flow, can be estimated, and then from cumulative raw numbers, you can infer grade-specific raw net-flow numbers (and thus rates).

Listen to this articlePosted in Research on March 20, 2004 1:09 PM |