Early Career Researcher registration type constitutes within 5 years of the terminal degree.
See also different:
Tier 1 individual membership
Tier 1 Participants from high-income countries http://data.worldbank.org/income-level/HIC
Tier 2 individual membership
Tier 2 Participants from middle-income countries http://data.worldbank.org/income-level/MIC
Tier 3 individual membership
Tier 3 Participants from low-income countries http://data.worldbank.org/income-level/LIC (list of countries pasted below) Participants who do not have a job as academic or professional in university, government, hospital, or private compan [...]