Equation 3 · Part 1 · Demography, Migration, and Urban Futures in Practice: An Advanced Technical Guide
Symbol t
What this part means
t is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Its job in the formula
t is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.
Full expression→Symbol t→Article meaning
The passage around this formula
Aging the cohort forward. For each one-year (or five-year) step, every age-sex cohort is advanced by applying an age-specific survival ratio — the probability of surviving from one age to the next, derived from a life table built out of registered deaths and mortality schedules — and then subtracting deaths and adding net migrants assigned to that same age and sex [ 1 ] . Symbolically, for a cohort of age a and sex s in year t :
Learn the underlying idea
A variable is a named place for a value. Its letter is a local label: x can mean position in one formula and a data point in another.
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Sources cited in the surrounding passage
These citations provide research context; check each source for the exact claim it supports.