The population projections published by Statistics Iceland in 2022 are based on new statistical models of fertility, mortality and migration and their combined predictions. The projections are built by applying standard statistical and demographical methods. The new models and methods described in this paper allow us, in addition, to produce local projections and to incorporate the probability of overestimating the resident population. The overestimation effect is due to a lack of deregistration, e.g. the estimated resident population is about 2.5% smaller than the registered population. The results of the new population projections consist of predicted values as well as their associated uncertainty measures.
The projection method does not include any effects due to possible crises caused by natural, social or economic factors, nor the number of refugees. For instance, the predicted population growth for the year 2022 is 2.02% while the observed, register based growth during 2022 was 3.06%. The difference is entirely explained by the unusually high refugee flow which accounted for a 0.96% additional change in population. The national and local projections will be updated as soon as auxiliary, prior information becomes available and users, planning and administration factors and policy makers are invited to provide feedback of qualitative and/or quantitative type to Statistics Iceland for that purpose.
Methodology of population projections based on hierarchical Bayesian models — Statistical Series