While the name Andrea is male in Italy, Andrea is a female name in Germany and can even be both in the US. In this case, we provide an accuracy value in the query result, ranging between 0 and 100 (or a probability value between 0 and 1). It tells you how certain we are in having detected the correct gender. You can significantly increase the API's result quality by providing some geographical information about your query. This can either be a country code, the browser's locale, or an IP address. You can learn more about localizing a query in our API docs.