Should I use 863 fields or the 866?
When editing a Local Holdings Record that has its data in an 866 field, should the data be moved to 853 and 863 fields, and then would we delete the 866 field?
We try to avoid using the 866 field if the holdings can be expressed in the 853 and 863 fields. So if you are editing a record that has an 866, check to see if you could use 853 and 863 fields instead.
There are some holdings which do not use the 853/863 fields, such as temporary holdings. But even these holdings aren't best represented in an 866 text field.
Remember that you can have multiple 863 fields in the LHR, which allows us to describe holdings with gaps. Many of the records that ended up with 866s in the course of migration have gaps that the system couldn't automatically translate to the 863. If you create 863 fields for this type of LHR, then the 866 info would be redundant and can be deleted.
Almost the only time I've used the 866 field in an LHR is when I have a holding with lots of gaps, and I want to specify the gaps in our recent issues. Then I can end up with multiple 863s that show what my holdings actually are in detail. But sometimes I want to summarize or list older holdings with less specificity - because I don't want a long, hard-to-read LHR and because traffic in older items is generally lower than recent issues. So I may use an 866 to summarize the earlier holdings. Retrieve record #9813336 and look at the holding for MNU if you want to see an example of this type of holding.