Table 1.

Cohort measures of migration.

Source: Bernard (2017a)

Measures	Definition	Methods	Equations
Completed migration rate	Average number of migrations per individual by the end of their migratory life	$\text{CMR}=M/P$	(1)
Completed migration distribution	Proportion of a cohort who migrated exactly i times	${\text{CMD}}_{\left(0,i\right)}=\frac{P_i}{P}$	(2)
Migration progression ratios	Proportion of a cohort who migrated i times and who went on to migrate at least once more	${\text{MPR}}_{\left(i,i+1\right)}=\frac{M_{i+1}}{M_i}$	(3)
Mean age at migration	Mean age at which individuals in cohort migrated	$\text{MAM}={\sum }_{n=1}^N{\sum }_{i=1}^I{X}_{n,i}/M$	(4)
Order-specific mean age at migration	Mean age at which individuals in cohort migrated for the ith times	${\text{MAM}}_i={\sum }_{n=1}^N{X}_{n·i}/M_i$	(5)
Mean migration interval	Average interval between all migrations for individuals who migrated at least twice	$\text{MMI}={\sum }_{i=1}^I({\text{MMA}}_{i+1}-{\text{MMA}}_i)/{\sum }_{i=2}^I{M}_i$	(6)