Many thanks to Judith Siess of Information Bridges International for sharing with me a previous issue of her One-Person Library newsletter on the subject of metrics. The issue called, Statistics and Library Advocacy is a useful one as it addresses not only those statistics we should collect for assessment purposes, but also those numbers we should collect for marketing purposes. Judith advises,
"Statistics can serve a valuable purpose—proving your worth to your parent organization. When presenting your case to management, you must use techniques and terms that they understand: cost-benefit analysis, unit-cost analysis, value added, and the like. Use spreadsheets to illustrate your points. By using statistics and relatively simple calculations you can show that the value of what you do easily meets or exceeds the amount your institution spends on the library (including salary and benefits, the collection, subscriptions, online services, floor space, air conditioning, water/sewer, and telephone). But you must be specific and have the data to back up your case."Also, Judith suggests (and I agree), that you should back up stats with stories whenever you can. Doing so makes the numbers more meaningful. Ultimately, it's necessary to figure out why you're collecting statistics before you start considering how to go about it. Otherwise, you could get buried in numbers that serve no purpose and don't help your case, whatever it may be.
Judith kindly allowed me to post her articles in full (PDF), so enjoy!