Author Question: A study that followed, over a 20-year period, 500 users and 500 non-users of oral contraceptives to ... (Read 68 times)

abc · **on:** Jul 8, 2018

A study that followed, over a 20-year period, 500 users and 500 non-users of oral contraceptives to determine if there were any long-term side effects would be which of the following?

A) Time series
B) Retrospective study
C) Prospective study
D) Crossover study

Question 2

Studies that collect data at one point in time are called which of the following?

A) Time series
B) Cross-sectional studies
C) Longitudinal studies
D) Crossover studies

thall411 · **Reply #1 on:** Jul 8, 2018

Answer to Question 1

C
Feedback:
In prospective cohort designs, researchers begin with a possible cause, and then subsequently collect data about outcomes. Retrospective designs (case-control designs) involve collecting data about an outcome in the present and then looking back in time for possible causes. In a time-series design, outcome data are collected over a period of time before and after the intervention, usually for a single group. In crossover designs, people are exposed to more than one experimental condition in random order and serve as their own controls.

Answer to Question 2

B
Feedback:
Cross-sectional designs involve the collection of data at one time period, whereas longitudinal designs involve data collection at two or more times over an extended period. In a time-series design, outcome data are collected over a period of time before and after the intervention, usually for a single group. In crossover designs, people are exposed to more than one experimental condition in random order and serve as their own controls.