Disentangling population- and household-level historical trends in wealth using rent records from the Isles of Scilly

Wealth is important to health, wellbeing and life-history decisions, and hence hasbroad implications for society. Mean per capita wealth is widely measured and,in many countries, has increased over time. However, while mean wealthincreases, so too can inequality, highlighting that these population-level trendsmay not align with individual experiences. Before we can understand what thesetrends mean for people’s lives, or design interventions to improve them, we needto disentangle whether they are driven by individuals becoming wealthier or by achange in the population composition, where poorer individuals are displaced bywealthier individuals. We used historic data from the Isles of Scilly on annualproperty rental values, which serve as a proxy for household wealth in thispopulation, to model both the within-household and between-household trendsover time. We also looked at whether the rate of change in wealth over timediffered between households and whether this contributed to increasedpopulation-level inequality. We found that the increase in mean annual rentalvalues was driven predominantly by households becoming wealthier. Those whopaid higher rents overall also experienced steeper increases in wealth. However,while the Gini coefficient of wealth inequality rose by 40.1% over the study period,the annual increase was not statistically significant. We relate these findings tocontemporaneous policy changes and shifts in individual life-histories.