Spatial stratified heterogeneity of fertility and its association with socio-economic determinants using geographical detector: The case study of Crete island, Greece

Research efforts related to better understanding and capture of the fertility trends over the time are considered to be of significant interest in the fields of demography and social sciences. In Greece, the overall relationships between fertility and numerous determinants that influence it have been explored at national level. However, the possible spatial heterogeneity in these relationships has not been investigated at any spatial level. The main objective of this study was to explore the spatial stratified heterogeneity in the relationships between fertility and seven socio-economic determinants at the municipality level of Crete Island, Greece. By using demographic data from two censuses in 2001 and 2011, the fertility was measured as crude birth rate (CBR) and the determinants were created as attributes of urbanization, population density, immigration, marriage, female educational level, female unemployment and male employment. The spatial distributions of fertility and determinants for each year as well as their temporal changes were firstly identified. The majority of municipalities of Crete presented high fertility levels in 2001. Between 2001 and 2011, they showed a decline trend, with some exceptions from municipalities located in the north and south of its four prefectures. Furthermore, the Geographical Detector (GeoDetector) technique was applied to reveal the impact of each determinant and their interactions on fertility. The output results revealed that there was obvious spatial stratified heterogeneity of fertility in the island, which could mostly be explained by the immigration in 2001, and the urbanization and population density in 2011. The impact of marriage and female educational level was lower in both years and different (either positive or negative) among the years. The single effects of the prominent determinants were found to be significantly improved from their interactions.