Salvete!       Here's my soapbox answer for that. https://flowingdata.com/ Old but good: https://flowingdata.com/2010/01/21/how-to-make-a-heatmap-a-quick-and-easy-so... https://www.ideals.illinois.edu/bitstream/handle/2142/47285/274_ready.pdf?se... Watcher's / listener's advisory: http://liveplasma.com/artist-The%20Beatles.html   - How do I know when to purchase more in particular collection?      (When demand for materials in a given range has fallen flat or spiked. The former is particularly important since you'll encourage a self perpetuating problem if it's not addressed yet is in the scope of your collection. Figuring out why demand has fallen flat or spiked is key to solving this issue. Is it due to an already strong showing in a certain range that attracts Patrons with an interest in that subject matter? This might also manifest in your budget. When is the last time you allocated a substantial amount of money to a given range? Is it due to the age of that range? In that case a diagnostic could be Nicole's SQL query: SELECT itype, avg(mid(ExtractValue(marcxml,'//controlfield[@tag="008"]'),8,4)) FROM biblioitems LEFT JOIN items USING (biblioitemnumber) WHERE SUBSTR(ExtractValue(biblioitems.marcxml,'//controlfield[@tag="008"]'),8,4) REGEXP '[0-9]{4}' GROUP BY itype     - How do I judge demand ...for a particular collection?       (Talk to real live breathing Patrons both inside and outside your Library. Their feedback is essential since you might hear good things like "Actually you have just what I need all of the time." or terrible things like "I never use this collection for that since it's so old." Circulation data are the traditional go to for this [number of circs across X shelving location, author, et cetera.])   - How do I decide which items will perform in this branch      (Branches tend to come in local flavors, so again, this is drawn more from interaction than data. Another angle of this that is important are the demographics for the branch. It's always about matching the user to the book and vice versa. That said, you might decide that you want to nudge a collection into new waters to force Patrons to explore, or have space that is terrific for a certain type of material, et cetera. [This will tend to be item type data that might address questions like - Is this a DVD heavy location or do folks prefer hard copy books? ]      Price to earnings for a library is cost of a given material / number of circs.  (Not exactly, but don't at me.) Bring your director on board to run an experiment that can be treated like the fantasy portfolios you'd assign to kids to teach them how stocks work.  Give each bibliographer a budget and ensure that they track their purchases. Monitor circs per item over a certain period of time. How do those circs change quarter to quarter? Are your bibliographers getting better or worse over time? It's not only about cost to circ - if you only develop this way, you'll regret it since the overall impact of your collection will fall flat and be less rich. There are larger ticket items that will not circ too much yet be prized in your collection for a very long time. Just as there are circ horses that pack a big punch for their buck, yet don't really lend much to enrichment or education.      Seriously, use the conspectus method. http://www.varastokirjasto.fi/kokoelmakartta/julkaisut/esitelmat/Mary_Bushin...      Compare how you fare with your neighbors and observe consortial duties. Are you deciding to deliberately be different from your neighbors or are you collecting to replicate their success?  Are you charged with collecting a certain subject matter in depth in your consortium? Cheers,Brooke