[FEATURE] LEHD Employment

[GregorSchroeder]

Is your feature request related to a problem? Please describe

SANDAG has not produced estimates of employment for the San Diego region in many years, although it was once a standard annual product. This work explores the reintroduction of employment estimates. The Census LEHD LODES program is the only known publicly available source of employment data available. As such, it will form the basis of any potential employment estimates methodology.

Describe the solution you'd like

For a given year,

1. Take the most recently available Census LEHD LODES block-level data
   a. Check that LODES8 uses 2020 Census blocks back to 2010
   b. Check what NAICS version the LODES8 uses back to 2010
   c. Check mgra version of the given estimates run and grab appropriate cross-reference for MGRA series to Census blocks
   d. Return Census LEHD LODES by MGRA by 2-digit NAICS code except for 72 which must be split into 721 and 722

2. Take the BLS QCEW annual average for the given year
   a. Get this by 2-digit NAICS code except for 72 which must be split into 721 and 722
   b. Check what NAICS versions are used by BLS QCEW back to what year and if that materially affects 2-digit NAICS code and the 721 and 722 split
   c. Exclude NAICS code 99 (could also scale every NAICS by missing NAICS code 99 employment)
   d. Return BLS QCEW data by NAICS

3. Control the Census LEHD LODES data by NAICS code to match the BLS QCEW annual average and integerize preserving regional totals.

Describe alternatives you've considered

This is all preliminary exploration work to determine best practice moving forward. Still under development wherein a range of alternatives may be explored in the future.

Additional context

https://github.com/SANDAG/BLS
https://github.com/SANDAG/Census-LEHD