• Develop a research question in developmental psychology.
• Create 3 separate designs: a longitudinal, cross-sectional, and sequential research design to examine that topic.
• You choose (when applicable, depending on design type):
  • The time length in years you want the study to be conducted for.
  • How often the observations would occur.
  • The number of age groups.
  • Which age(s) are included in each age group.
    • Make sure you give a rationale/reason for all your decisions

Example:

So my research question is going to be: How do testosterone levels change in men across the lifespan? 1. Longitudinal study: I am going to take a group of 100 1-year old male babies and examine them for their entire lifespan (so as long as possible). They will be tested every year during a yearly physical. I chose once a year for testing so that it wouldn't be too inconvenient for the participants or their guardians, and since a yearly physical is fairly common, I think that would be a good time to do the test. 2. Cross-sectional: Given I am interested in the entire lifespan for my research question, I am going to have quite a few age groups. I will select a group of 50 males for each single age from 1 to 80 (1 y/o, 2 y/o, 3 y/o, etc.). This would be a total of 4000 participants. I chose the age groups to only be a year interval because the testosterone levels could change quite a bit, especially in puberty and old age, in just a few years. Each participant would only be tested once, and all the participants would be tested around the same time frame. The entire study should only take about a month. 3. Sequential: I will also have 50 males in each age group. This time, I will have them in each single age group from 1 to 60. I am going to test each age group for 20 years. So every participant will be in the study for a total of 20 years. As with the longitudinal design, I will test participants once a year. I made the last age group for this design as 60 given that I want to study each participant for 20 years and factoring in the average lifespan.