In the Netherlands, as in many other countries, annual fluctuations in
net migration are larger than those in births and deaths. As a result
, forecasts of net migration are an important source of errors in popu
lation forecasts, particularly in the short run. In order to make it p
ossible for the user to judge the usefulness of a population forecast,
the forecaster should give an indication of the degree of uncertainty
of the forecast of net migration. An ARIMA model can be used for spec
ifying a statistical forecast interval. As the width of forecast inter
vals for migration in single years differs strongly from that of an in
terval for average migration during the forecast period, it is importa
nt that the forecaster indicates which type of interval is presented,
A comparison of forecast intervals for net migration obtained from an
ARIMA model to intervals in official Dutch national population forecas
ts shows that the uncertainty on migration has been underestimated in
past official forecasts.