The authors commented a high level of marriage homogamy observed in prior studies in Norway. They note that most of those studies were ethnographic or based on national statistics assessing homogamy over a short period of time.
The population of this study that researchers report was based on a sample of 129 651 people from the 1980 Census. From this data pool, researchers created a sample of couples. They analyzed educational homogamy patterns across five ten-year cohorts born between 1900 and 1949. Their findings revealed a decrease in educational homogamy throughout these cohorts, both in absolute terms and when allowing for the general rise in educational level across time.