The age of majority is the threshold of adulthood as recognized or declared in law. The age of majority in international research can be defined by the laws, customs, and norms in the area or a country in which the research will be conducted.
In general, the age of majority can be defined as the moment when individuals receive legal control over their actions, decisions, and themselves. At this moment, guardians and parents stop having legal responsibilities of taking care of their children. Individuals become adults recognized by law when they reach this age.
For a large number of countries, the age of majority starts when a person becomes eighteen years old. However, there are higher and lower thresholds depending on the jurisdiction of a particular government.
The word majority in the expression refers to being of full age and is in contrast with minority, which is a state of being a minor, or a person under age. Age of majority does not refer to the ages of sexual consent, maturity, drinking, or driving, as these may be set at a different age. The example of it is the difference between the minimum age to purchase alcoholic drinks and the age of majority in the United States.
As mentioned above, various countries may define the age of majority differently, which may be a problem for international research. However, all possible issues can be resolved because the age of majority in research depends on the laws and norms of the country a study is performed in. It means that if researchers from the United States collect data in India and Indian individuals are included into the sample, they should consider the laws indicating the age of majority in the country.