The Key Statistics for Trustees section of LRS-i provides ready access to selected statistics which best summarize the general health of a public library. These key statistics should be of particular interest to public library trustees who are interested in assessing the status of their library in relation to other Colorado public libraries. The five statistics in this group are total staff per 1,000 served, total operating expenditures per capita, library visits per capita, circulation per capita, and program attendance per 1,000 served.
Why focus on these five statistics—out of the dozens reported annually by public libraries—to get a sense of the general health of a library? The relationships among these statistics, and between them and all of the other public library statistics, are noteworthy in two ways.
First, these five statistics are the ones most highly correlated with each other, of all the statistics collected.
Second, each of these key statistics is also highly correlated with multiple other statistics that are not included in this list. While many of the remaining public library statistics are correlated with each other, some are correlated less strongly and/or with fewer other statistics. On that basis, other statistics were excluded in favor of the five that made this list.
For instance, one might wonder why volumes per capita or collection turnover rate is not included. That is explained by the fact that both of those statistics are strongly predicted by total operating expenditures per capita. If a library spends more on a per capita basis, it is therefore safe to assume that it will have larger and more current holdings that are likely to be borrowed more frequently.