A developmental psychologist wants to survey several cohorts of people aged 60-years-old to get their opinions concerning medicare (e.g., assessing 60-year-olds in 2010, then another group of 60-year-

A developmental psychologist wants to survey several cohorts of people aged 60-years-old to get their opinions concerning medicare (e.g., assessing 60-year-olds in 2010, then another group of 60-year-olds in 2015, and yet another in 2020). which research design is best suited to this task?