Traditional censuses and population registers are considered to be solid sources for assessing long-term migration. E.g. census and population registers cover the entire population and contain a wide range of indicators, which allows disaggregating the migrants by various characteristics. The results of the population census are comparable worldwide as countries follow the international recommendations.
Measuring short-term and everyday mobility requires more flexible methods, such as various registers and indirect databases, satellite-based methods, or modern sensing technologiesbecause classical data sources are designed to describe the resident population. While traditional data sources such as the census or register data contain data about the existence of another home, these sources do not offer extensive information regarding the amount of time spent there and year-round activities.
The use of MPD has the potential to improve several aspects of migration statistics, such as timeliness (in some cases up to near real-time), access to statistical information previously not available (new indicators), calibration opportunities for existing data, space and timely resolution/granularity (i.e., the scale or level of detail in a set of data) and accuracy.
The advantage of MPD-derived information is its automatic (independent) collection and relatively low costs. However, MPD do not cover the entire population, and therefore, it is not possible to extract all possible migration events. In addition, it should be considered that MPD includes noise and erroneous records, and special care should be taken to clean the data of errors and noise because they might affect the final result.
The MPD cannot be a replacement, but rather a supplementary source for the official migration statisticsobtained from traditional sources.