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Multilingual Demographic Dictionary, second unified edition, English volume

Index of net velocity

Multilingual Demographic Dictionary, second unified edition, English vol.
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Index of net velocity  (INDEX of net velocity)


In studying migrants between two areas during a period, one commonly used measure is the index of migration intensity 1, obtained by dividing the number of migrants from area A to area B by the product of the number of inhabitants in B at the end of the period, and the number of inhabitants of A at the beginning of the period who are still alive at the end. This index, divided by the ratio of the total number of migrants to the square of the population of the country, yields a migration preference index 2. When the numerator is restricted to the net stream of migration, the resulting measure is called an index of net velocity 3. The effectiveness of migration streams 4 is measured by relating the absolute value of the net migration stream to the gross interchange (805-10).

  • 1. This index can be interpreted as the probability that two individuals alive at the end of the period selected randomly, one among those residing in area A at the beginning of the period, and the other among those residing in B at the end of the period, will be identical. The availability of data may impose various other denominators.

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