Population Growth Calculation

Joint Budget Committee. Section 20 of article X of the state constitution (TABOR) requires the maximum annual percentage change in state fiscal year spending to equal inflation plus the percentage change in state population in the prior calendar year adjusted for revenue changes approved by voters. Although TABOR does not specify how the state shall determine the percentage change in state population (population growth), the TABOR implementing statutes do. For years in which there is not a decennial census, the TABOR implementing statutes require the state to calculate population growth by determining the percentage change between:

• The federal census bureau's estimate of state population (census estimate) for the previous calendar year, as of December in the current calendar year; and
• The census estimate for the current calendar year, as of December in the current calendar year.

The current method for calculating population growth can lead to either double-counting or under-counting population changes in census estimates. If the federal census bureau revises a census estimate upward for a given year:

• The calculated population growth between the given year and the immediately preceding year will be understated, since the population growth between those years is based on an inaccurately low census estimate for the given year; and
• The understated population growth between the given year and the immediately preceding year is not corrected or carried forward when calculating population growth for subsequent years, as those calculations are based on the revised census estimate for the given year.

Put differently, if the federal census bureau revises a census estimate upward for a given year, population growth will be understated and the fiscal year spending limit will be lower. The opposite is true if the federal census bureau revises a census estimate downward. In either case, under the current method for calculating population growth, population growth would be measured inaccurately.

The bill adjusts the method of calculating population growth. Under the bill, population growth is calculated by determining the percentage change between:

• The census estimate, as of December in the previous calendar year, for the previous calendar year; and
• The census estimate, as of December in the current calendar year, for the current calendar year.

This approach prevents double-counting or under-counting population changes as a result of revised census estimates and results in a more accurate measurement of population growth.

The bill also makes conforming amendments.

(Note: This summary applies to this bill as introduced.)