Public libraries data are generated as Excel spreadsheets from the KOSTRA database. Each row represents one municipality.
- The rows are distributed among five sheets by population size: above fifty thousand, 20-50, 10-20, 5-10, below five thousand.
- Municipalities that no longer exist are removed. The rows that remain constitute our basic data.
- Within each sheet the municipalities are also ordered by population size.
- The two municipalities Tønsberg and Nøtterøy, which operate a joint library system, are treated as a single unit.
Each sheet with basic data is followed by an indicator sheet. Here indicator values are calculated interactively from the basic data. This means that changes to the basic data will automatically be reflected in the indicators. We do not replace missing indicator – or basic – values by imputed numbers.
- When crucial indicator values are missing, the municipalities concerned are removed from the calculations.
- We do this by moving them to the bottom of the indicator sheet, where they are marked in red.
The process is iterative. Often, missing values only become evident during the data processing.
- In such cases, indicator values may have to be recalculated after the «offending» municipalities have been removed.
- Since the indicator sheets are interactive, this is easily done – as long as we remember to do it.