cohort effect

{{Short description|Social science term related to shared experiences}}

The term cohort effect is used in social science to describe shared characteristics over time among individuals who are grouped by a shared temporal experience, such as year of birth, or common life experience, such as time of exposure to radiation.{{Citation |last=Atingdui |first=Norissa |title=Cohort Effect |date=2011 |url=https://doi.org/10.1007/978-0-387-79061-9_617 |encyclopedia=Encyclopedia of Child Behavior and Development |pages=389 |editor-last=Goldstein |editor-first=Sam |access-date=2023-07-27 |place=Boston, MA |publisher=Springer US |language=en |doi=10.1007/978-0-387-79061-9_617 |isbn=978-0-387-79061-9 |editor2-last=Naglieri |editor2-first=Jack A.|url-access=subscription }}{{Cite journal |last=Ryder |first=Norman B. |date=1965 |title=The Cohort as a Concept in the Study of Social Change |url=https://www.jstor.org/stable/2090964 |journal=American Sociological Review |volume=30 |issue=6 |pages=843–861 |doi=10.2307/2090964 |jstor=2090964 |pmid=5846306 |issn=0003-1224|url-access=subscription }} Researchers evaluate this phenomenon using a cohort analysis.{{cite web |title=Age-Period-Cohort Effect Analysis {{!}} Columbia Public Health |url=https://www.publichealth.columbia.edu/research/population-health-methods/age-period-cohort-analysis |website=Columbia University Mailman School of Public Health |language=en |date=3 August 2016}}

For economists, the cohort effect is an important factor to consider in the context of resource dependency.{{Citation needed|date=February 2025}} This is because cohorts, which in organizations are often defined by entry or birth date, retain some common characteristic (size, cohesiveness, competition) that can affect the organization.{{cite web |last1=Deno |first1=Frank |title=A Quantitative Examination of the Relationship between Servant Leadership and Age on Organizational Commitment in Faith-Based Organizations |url=https://digitalcommons.liberty.edu/cgi/viewcontent.cgi?article=2606&context=doctoral}} For example, cohort effects are critical issues in school enrollment.

The cohort effect is relevant to epidemiologists searching for patterns in illnesses.{{Citation needed|date=February 2025}} Cohort effects can sometimes be mistaken for the anticipation phenomenon, which is the earlier onset of genetic illnesses in later generations. {{cite web |title=Further Evidence of a Cohort Effect in Bipolar Disorder: More Early Onsets and Family History of Psychiatric Illness in More Recent Epochs arly Onsets and Family History of Psychiatric Illness in More Recent Epochs |url=https://www.psychiatrist.com/jcp/cohort-effect-in-bipolar-disorder/ |website=Psychiatrist.com}} There is evidence for both a cohort effect and an anticipation effect in the increase in childhood-onset bipolar disorder.