Copied from Marybeth's 8/12/11 email, "More than 4 holds"
Basically we follow a 4:1 holds ratio for our print materials. Four holds for each copy of a title. When the number of holds exceed this ratio we buy more copies. I monitor a report every day that provides this information so we can get the additional copies ordered so we can get the holds moving. We have found that this system allows us to be more conservative in our purchasing (especially as our collection budget has been reduced) without sacrificing popular materials and what our customers are requesting. It is important to note that when the system is calculating the hold ratio it uses the unique ISBN. Therefore, for those titles that have circulating copies AND PopPicks, both are included to determine the ratio.
Holds for CD music and DVDs are monitored a little differently. Our holds ratio is higher (usually 6:1 or higher) primarily because of the 7 day checkout. We also use the "rotten tomato" rating guide to determine additional purchases.
I would ask those staff members who work with the Friends (Used Books) to review the procedure for adding items to the collection. Donations of some of the latest bestsellers have really helped with some of these long hold lists.