What does the immigration rate measure?

The immigration rate specifically measures the number of immigrants arriving at a destination in relation to the population size, typically expressed per 1,000 individuals. This metric allows for an understanding of how a population is changing due to immigration, indicating how many individuals from outside a region are moving into it, making it crucial for assessing the impacts on social services, labor markets, and cultural dynamics within the destination community.

The other options do not accurately define the immigration rate. For instance, measuring the number of emigrants leaving a country refers to emigration, not immigration. Discussing overall migration trends provides broader insights that could encompass both immigration and emigration without focusing on arrivals alone. Lastly, considering the average age of the population pertains to demographic studies but does not relate directly to immigration rates. Thus, the second option is the most precise and relevant explanation of what the immigration rate indicates.