Which of the following is not a significant drawback of conducting a longitudinal study? 1. they are effective in determining variable patterns over time. 2. they can ensure clear focus and validity. 3. they would risk experiencing panel attrition. 4. they require a large sample size.

I believe the answer is: 4.They require a large sample size.

The data required in a longintudinal study is taken by examining the sample population for a long period of time, as they develop over the years. The amount of population in such studies is usually really small, but the amount of time needed for start to finish is the one that become the main problem among researchers