A Look at CDRPC’s Population Projections

In the early 2010s, the Capital District Regional Planning Commission (CDRPC) introduced population projections for the Capital Region, based on a log-linear formula that anticipated a gradual population decline. These projections relied on historical census data and regional trends to predict future demographic changes. With the release of the 2020 Decennial Census data by the Census Bureau, it is crucial to compare CDRPC’s projections with the actual population counts. This comparison is essential for assessing the accuracy and reliability of CDRPC’s demographic predictions.

To assess the accuracy of CDRPC’s population projection compared to the actual population in 2020, the percent deviation (Percent Deviation = [(Actual Population – Projected Population) / Projected Population] * 100%) was used. A positive percent deviation suggests an overestimation, a negative value indicates an underestimation, and a value close to zero reflects a more accurate projection. This method helps quantify the extent of the projection’s accuracy in predicting population changes over time.

While population projections are vital for policy planning, resource allocation, and infrastructure development, the actual population data serves as a reality check. Analyzing the disparities between projected and actual population numbers allows for the refinement of forecasting methodologies, the identification of potential biases, and a deeper understanding of the complex factors influencing demographic trends. This examination helps governments, organizations, and researchers make more informed decisions and adapt strategies to meet the evolving needs of growing or declining populations.

Moving forward, CDRPC will collaborate with Cornell’s Program on Applied Demographics to develop improved projection models for the Capital Region, enhancing the region’s capacity for effective long-term planning and development.

Municipal/County Projections

Here are some of the municipalities that had actual populations that deviate most significantly from CDRPC projections.

Albany County:

1. Village of Menands (-11.40% difference)
2. Town/Vil. of Green Island (-12.50% difference)
3. City of Cohoes (-9.66% difference)

Schenectady County:

1. Town of Duanesburg (Deviation: 9.11%)
2. Town of Princetown (Deviation: 9.16%)
3. Village of Delanson (Deviation: 11.84%)

Saratoga County:

1. Village of Galway (Deviation: 18.72%)
2. Town of Ballston (Deviation: -13.26%)
3. Village of Round Lake (Deviation: -30.81%)

Rensselaer County:

1. Village of Valley Falls (Deviation: -11.35%)
2. Village of Schaghticoke (Deviation: 9.76%)
3. Town of Petersburg (Deviation: 11.83%)

Age Cohort Projection Comparison

In addition to the municipal and county-level projections, CDRPC also published age cohort projections for 2020. These age cohort projections have been compared with the actual population counts from the 2020 Census.