Currently the logic for deduplication compares DOB activity with the total unit count for neighborhood rezonings (I think this is generally true of all sources, but I think the change could be limited just to this specific case). This is a particular issue for neighborhood studies since they phase in over multiple time bands.
In the case of a 5k unit rezoning over a 10 year period we would estimate 2.5k within 5 years and 2.5k between 5 and 10 years. If we deduplicate 3k DOB permits against the full 5k unit count, we would then be splitting the remaining 2k between both time bands. Instead of 3k (DOB) in the <5 bucket and 2k (Rezoning) in the 5-10, we would get 4k (DOB+Rezoning) and 1k. Table below for additional explanation:
What is happening:
<html xmlns:v="urn:schemas-microsoft-com:vml"
xmlns:o="urn:schemas-microsoft-com:office:office"
xmlns:x="urn:schemas-microsoft-com:office:excel"
xmlns="http://www.w3.org/TR/REC-html40">
Source | Total Units | <5 | 5to10
-- | -- | -- | --
Rezoning | 5000 | 1000 | 1000
DOB | 3000 | 3000 | 0
Total | 5000 | 4000 | 1000
Currently the logic for deduplication compares DOB activity with the total unit count for neighborhood rezonings (I think this is generally true of all sources, but I think the change could be limited just to this specific case). This is a particular issue for neighborhood studies since they phase in over multiple time bands.
In the case of a 5k unit rezoning over a 10 year period we would estimate 2.5k within 5 years and 2.5k between 5 and 10 years. If we deduplicate 3k DOB permits against the full 5k unit count, we would then be splitting the remaining 2k between both time bands. Instead of 3k (DOB) in the <5 bucket and 2k (Rezoning) in the 5-10, we would get 4k (DOB+Rezoning) and 1k. Table below for additional explanation:
What is happening: <html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" xmlns:x="urn:schemas-microsoft-com:office:excel" xmlns="http://www.w3.org/TR/REC-html40">
Source | Total Units | <5 | 5to10 -- | -- | -- | -- Rezoning | 5000 | 1000 | 1000 DOB | 3000 | 3000 | 0 Total | 5000 | 4000 | 1000