{"id":4048,"date":"2026-04-14T07:00:00","date_gmt":"2026-04-14T12:00:00","guid":{"rendered":"https:\/\/thesocietypages.org\/ccf\/?p=4048"},"modified":"2026-01-23T09:50:32","modified_gmt":"2026-01-23T15:50:32","slug":"dont-panic-population-projection-is-not-a-crystal-ball","status":"publish","type":"post","link":"https:\/\/thesocietypages.org\/ccf\/2026\/04\/14\/dont-panic-population-projection-is-not-a-crystal-ball\/","title":{"rendered":"Don\u2019t Panic: Population Projection is Not a Crystal Ball"},"content":{"rendered":"\n

Reprinted from CCF Research Briefs<\/em><\/p>\n\n\n\n

AUSTIN, TX, August 20, 2025<\/strong>\u2014Population panic \u2013 worries about \u201cdepopulation\u201d linked to low birth rates \u2013 has become pervasive, with dire predictions in both the short<\/a> and long<\/a> term. Yet demographers like us \u2013 experts who explicitly study population size, composition, and structure \u2013 are generally not highly concerned. Why is this? It\u2019s because we understand the strengths and limitations of population projections. Projections can accurately describe how populations will change if we know future birth, death, and migration rates. But demographers are well aware that they don\u2019t have a crystal ball \u2013 we can\u2019t fully anticipate economic shifts, political changes, global events, or how future generations will respond to their changing worlds. That\u2019s why the farther we project from the present, the less accurate those projections are likely to be.<\/p>\n\n\n\n

What are Population Projections?<\/strong><\/p>\n\n\n\n

In demography, our most common population projection tool is called cohort component projection<\/em>. This tool treats different age groups (cohorts<\/em>) separately, applying rates representing the three components<\/em> of population change \u2013 birth, death, and migration \u2013 to each one. A cohort component projection begins with a baseline population (usually based on high quality censuses and surveys) and our most recent birth, death, and migration rates. Then, we make our best guesses about birth, death, and migration rates for every year in the projection. At least initially, our best guess is that future rates will be similar to current rates. We apply our estimate of next year\u2019s rates to the baseline population, generating a projected population for the next year. Then we take this projected population and repeat the process, applying likely future rates for each year in turn until we reach the final projected year. To project a population fifty years into the future, we do this process fifty times, with each year\u2019s projections feeding into the next.<\/p>\n\n\n\n

Therefore, population projections require that we use expected birth, death, and migration rates for each year between the baseline data and the end of the projection. For example, if we want to project the US population in 2030 based on 2024 data, we must come up with likely birth, death, and migration rates for 2025, 2026, 2027, 2028, and 2029. And because it is a cohort-based model, it uses a separate birth, death, or migration rate for each 5- or 10-year age group. This can easily mean juggling dozens of rates just to project forward one year.<\/p>\n\n\n\n

The best way to get those dozens of rates for each year is to rely on current rates and recent trends. This works well when things are changing slowly and in predictable ways, but it means our projections are often limited to forecasting a future that\u2019s a lot like the present.<\/p>\n\n\n\n

How Good are Demographic Projections at Predicting the Future?<\/strong><\/p>\n\n\n\n

Historically, demographic forecasts have often not anticipated major changes in birth, death, and migration. For example, much like today, in the 1930s and 1940s many commentators bemoaned the low fertility of the time. Expert projections<\/a> of US population from the 1930s assumed that fertility would remain relatively constant into the future. They imagined fertility rates would continue as they were indefinitely, yielding rapid population aging and slow population growth. Yet fertility did not remain low \u2013 instead we got the Baby Boom. As a result, population projections from the 1930s and 1940s predicted actual future population size quite poorly.<\/p>\n\n\n\n

\"\"<\/a><\/figure>\n\n\n\n

To illustrate this point, the figure[1] to the right compares Social Security Administration population projections from 1946<\/a> (dotted lines) with the actual US population (solid black line). Four different projections were prepared in 1946, each making assumptions of birth, death, and migration rates at various levels. It is clear that even the most \u201coptimistic\u201d 1946 projection, represented by \u201cB\u201d line, underestimated the actual US population by 1950. Moreover, the magnitude of underestimation increased over time. This illustrates how differences between what we think birth, death, and migration rates might be \u2013 our assumptions about the future \u2013 and the actual course of events compound over time. Any differences between expected rates and actual future rates can yield increasingly large differences between population projections and the eventual reality.<\/p>\n\n\n\n

Human history demonstrates that the past is the best predictor of tomorrow\u2026right up until it isn\u2019t. At their best, population projections are well-informed extrapolations of current information. Things change \u2013 and the likelihood of change increases as periods of projection get longer. The discussions around low birth rates that warn of rapid aging, fiscal shortfalls, empty kindergartens, and ultimately population collapse all assume that current trends will continue indefinitely. We should all be skeptical of that.<\/p>\n\n\n\n

Acknowledgment<\/strong><\/p>\n\n\n\n

This work benefited from research, administrative, and computing support provided by the University of Colorado Population Center, funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) (Project 2P2CHD066613-06); the Carolina Population Center, funded by NICHD (Project 5P2CHD050924-20); The Ohio State University\u2019s Institute for Population Research, funded by NICHD (Project 5P2CHD058484-15); and the Hopkins Population Center, funded by NICHD (Project P2CHD042854-20). The authors would like to thank the staff at CCF for their assistance with the production of this article and the CCF editorial board for their helpful comments in drafting this brief.<\/p>\n\n\n\n

FOR MORE INFORMATION, PLEASE CONTACT:<\/strong><\/strong><\/p>\n\n\n\n

Amanda Jean Stevenson
Associate Professor, Department of Sociology
Director of Population Program, Institute of Behavioral Science
University of Colorado Boulder
Amanda.Stevenson@Colorado.edu<\/a><\/p>\n\n\n\n

BRIEF REPORT:<\/strong> https:\/\/sites.utexas.edu\/contemporaryfamilies\/2025\/08\/20\/population-brief-report\/<\/a><\/p>\n\n\n\n

_____________________________________<\/strong><\/p>\n\n\n\n

[1]Projections: Myers, Robert J. Projections from Illustrative U.S. Population Projection, 1946. January 1948. Office of the Actuary, Social Security Administration. https:\/\/www.ssa.gov\/oact\/NOTES\/pdf_studies\/study024.pdf<\/a><\/p>\n\n\n\n

Decennial populations 1950-2010: https:\/\/www.census.gov\/data\/tables\/time-series\/dec\/popchange-data-text.html<\/a><\/p>\n\n\n\n

Estimated actual population for June 5, 2025: https:\/\/www.census.gov\/popclock\/<\/a><\/p>\n\n\n\n

_____________________________________<\/strong><\/p>\n\n\n\n

ABOUT CCF<\/strong><\/p>\n\n\n\n

The Council on Contemporary Families<\/strong><\/a>, based at the University of Texas-Austin, is a nonprofit, nonpartisan organization of family researchers and practitioners that seeks to further a national understanding of how America\u2019s families are changing and what is known about the strengths and weaknesses of different family forms and various family interventions.<\/p>\n\n\n\n

The Council helps keep journalists informed of new and forthcoming research on gender and family-related issues via the CCF Network. To locate researchers or request copies of previous research briefs, please contact Stephanie Coontz<\/a>, Director of Research and Public Education, at coontzs@msn.com<\/a>, cell 360-556-9223.<\/p>\n\n\n\n

Follow us! @ccfamilies.bsky.social<\/a>, [@CCF_Families]@CCF_Families, and https:\/\/www.facebook.com\/contemporaryfamilies<\/a>
YouTube: <\/strong>@contemporaryfamilies<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Reprinted from CCF Research Briefs AUSTIN, TX, August 20, 2025\u2014Population panic \u2013 worries about \u201cdepopulation\u201d linked to low birth rates \u2013 has become pervasive, with dire predictions in both the short and long term. Yet demographers like us \u2013 experts who explicitly study population size, composition, and structure \u2013 are generally not highly concerned. Why is this? It\u2019s because […]<\/p>\n","protected":false},"author":2124,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-4048","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/thesocietypages.org\/ccf\/wp-json\/wp\/v2\/posts\/4048","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/thesocietypages.org\/ccf\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/thesocietypages.org\/ccf\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/thesocietypages.org\/ccf\/wp-json\/wp\/v2\/users\/2124"}],"replies":[{"embeddable":true,"href":"https:\/\/thesocietypages.org\/ccf\/wp-json\/wp\/v2\/comments?post=4048"}],"version-history":[{"count":2,"href":"https:\/\/thesocietypages.org\/ccf\/wp-json\/wp\/v2\/posts\/4048\/revisions"}],"predecessor-version":[{"id":4051,"href":"https:\/\/thesocietypages.org\/ccf\/wp-json\/wp\/v2\/posts\/4048\/revisions\/4051"}],"wp:attachment":[{"href":"https:\/\/thesocietypages.org\/ccf\/wp-json\/wp\/v2\/media?parent=4048"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/thesocietypages.org\/ccf\/wp-json\/wp\/v2\/categories?post=4048"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/thesocietypages.org\/ccf\/wp-json\/wp\/v2\/tags?post=4048"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}