The Raiser's Edge Import tool can use either the Constituent ID or the Constituent Import ID to identify existing records when using import to update records. Which is the better field to use?
Either field can be used for Import to identify existing records in The Raiser's Edge.
However, there are some import set-ups that can only use the Constituent Import ID in its data. For example, importing a solicitor to a gift requires the Constituent Import ID from the solicitor's constituent record. So if you are unsure which field to use, consider using the Constituent Import ID by default so that the right data is present for any import used.
If you are exporting the data from The Raiser's Edge to create a data file, consider including both fields whenever possible and they're available.