Use this estimator for a transparent scenario based on an explicit base population and stated fertility, mortality, migration, or interpolation assumptions.

Headship rates

Age-specific headship rates as proportions from zero to one.

Adults

Projected adult population for the same age groups.

Households

Projected number of households.

Total adults

Total adult population covered by the projection.

A projection is conditional, not a prediction. Uncertainty increases with the horizon, and discontinuities in migration, boundaries, policy, fertility, or mortality can invalidate the assumed path.

Run multiple scenarios and compare them with a cohort-component projection when the necessary fertility, mortality, and migration schedules are available. Sensitivity ranges are more useful than a single extrapolated path.

• School Age Population Projection

  Project a school-age cohort to the next planning date with the census survival ratio method: survivors equal the current cohort times l(x+n)/l(x), plus net school-age migrants.

• Census Date Midyear Conversion

  Convert a census count taken on an arbitrary date to a mid-year equivalent by exponential interpolation at an assumed constant annual growth rate over the elapsed days between the two dates.

• Postcensal Intercensal Estimator

  Produce a postcensal estimate by the component method (base plus births minus deaths plus net migration since the census) or an intercensal estimate by linear interpolation between two censuses at a stated fraction of the interval.