After slogging through the long and often unwieldy 300s, it feels good to know that the 400s and 500s are some of the easiest-to-weed parts of a collection. It helps that, in most public libraries, the 400s and 500s are also the smallest parts of the collection.
This can almost exclusively rest on usage and condition. The field of languages and linguistics is stable and not particularly time-sensitive. And if you have plenty of space, don’t even worry much about your usage statistics. Some items, such as dictionaries, will be more readily used in the library rather than checked out, so you can keep those—if you have room and they are in good condition—even if your checkout numbers are low. If budget allows, replace English dictionaries and grammar classics when new editions are released.
Foreign language and English as a Second Language (ESL) or English language learners (ELL) materials may see high circulation and, therefore, need frequent replacement. In general, you need to keep at least one current dictionary for Spanish, French, German, and whatever other languages are studied or spoken in your community. Putting them in the circulating collection makes more sense than letting them gather dust in the reference collection. This section should also have learning materials in foreign languages that reflect the interests and needs of your community.
Weeding in the 400s is really an opportunity to fine-tune your collection. It’s likely that you may have a basic set of stock dictionaries, foreign-language materials, and ESL and ELL materials here. But do you know what your community currently needs? How long ago were most of those materials acquired? Have demographics in your area changed? Take this as an opportunity to purchase new materials as well as replacements for standards. Items receiving heavy use, such as Test of English as a Foreign Language (TOEFL) guides and ESL/ELL materials, should be replaced regularly with new copies and titles to maintain currency and freshness in the collection.
This is an area where new scientific discoveries, theories, and techniques can make an outdated collection useless. The 500s contain subjects in which information is quickly dated or even proven wrong (physics, astronomy, etc.), as well as subjects in which information is nearly timeless (mathematics), so keep a careful eye on publication dates in this section, and do your homework, if necessary. Pluto is not a planet, and there’s technically no such thing as a Brontosaurus. How old are your books on the International Space Station? Or on Mars expeditions?
Do your best to keep up-to-date in this section. It will be a heck of a job, for sure, but consider pulling everything five years and older for examination. Basic historical works on science, such as Darwin’s On the Origin of Species, should be retained, but weeding must be aggressive in the more time-sensitive areas to ensure the availability of accurate, up-to-date information. Let’s take a look at the breakdown of this section:
Weed based on condition and use, and check for outdated materials or safety standards. Consider asking a local classroom teacher to come in and evaluate the section. His experience (particularly as one who assigns such experiments) can be invaluable when deciding what to keep or replace.
Weed based on condition and use, but retain a collection of the basics—algebra, geometry, trigonometry, and calculus. Update with revised editions. In these times of Common Core, it’s important to make sure the materials you have reflect what today’s students are learning. As with the books on science experiments mentioned above, consider asking a local classroom teacher to come in and evaluate your collection for timeliness and completeness.
The field of space and astronomy changes rapidly, so keep on top of this section and weed on an annual basis when possible. Discard titles that include Pluto as a planet, books on old space missions, and titles that do not have an international balance. Stargazing books should be attractive and discuss relevant technology.
Weed books that do not reflect current theories and science on geological activities. Replace books that have outdated information on major disasters—such as the eruption of Mount St. Helens and the 2005 earthquake in Pakistan—with more current books that examine the long-term aftermath. Field guides for amateur fossil and rock hunters can be kept as physical condition and circulation allows.
It might not be obvious, but changes occur in this field as well. (Poor Brontosaurus.) Circulation should not be a factor in keeping outdated dinosaur books—the popularity of this topic with students may mean that even outdated books are checked out.
Weed and replace books on genetics, human biology, and evolution because of the rapid changes in scientific practices. Weed titles on ecology that appear dated—do you still have titles from the 1970s on the shelf? Update classics with newer editions, if possible. Keep an eye out for books that are sensational or political in tone.
Most of your botany books can stay, based on appearance. One thing to watch for would be field guides that promote edible or medicinal plants and herbs—ensure that they meet current safety guidelines.