Cal. Educ. Code § 54027

If a school district reorganizes either by unification or by consolidation with another school district of similar type, the Superintendent shall calculate an economic impact aid per pupil amount based on the respective per pupil amounts for each school district participating in the reorganization, weighted by the number of economic impact aid-eligible pupils contributed by each school district. The Superintendent shall use the appropriate data from the year prior to the year that the reorganization is effective for all purposes.