ORI Curriculum Examples




Case example for Experimental Studies

Definition : An experiment is a study in which a treatment, procedure, or program is intentionally introduced and a result or outcome is observed.

Experimental studies – Example 1

An investigator wants to evaluate whether a new technique to teach math to elementary school students is more effective than the standard teaching method. Using an experimental design, the investigator divides the class randomly (by chance) into two groups and calls them “group A” and “group B.” The students cannot choose their own group. The random assignment process results in two groups that should share equal characteristics at the beginning of the experiment. In group A, the teacher uses a new teaching method to teach the math lesson. In group B, the teacher uses a standard teaching method to teach the math lesson. The investigator compares test scores at the end of the semester to evaluate the success of the new teaching method compared to the standard teaching method.  At the end of the study, the results indicated that the students in the new teaching method group scored significantly higher on their final exam than the students in the standard teaching group.

Experimental studies – Example 2

A fitness instructor wants to test the effectiveness of a performance-enhancing herbal supplement on students in her exercise class. To create experimental groups that are similar at the beginning of the study, the students are assigned into two groups at random (they can not choose which group they are in). Students in both groups are given a pill to take every day, but they do not know whether the pill is a placebo (sugar pill) or the herbal supplement. The instructor gives Group A the herbal supplement and Group B receives the placebo (sugar pill).  The students' fitness level is compared before and after six weeks of consuming the supplement or the sugar pill.  No differences in performance ability were found between the two groups suggesting that the herbal supplement was not effective.

Discussion questions

1. What makes both of these studies experimental?

2. What type of information might the investigator collect in these two studies to see if the treatment (e.g. new teaching method or herbal supplement) is effective?

3. Can the researcher establish cause and effect in either or both of these two studies?

4. What would happen if the researcher allowed the students to study together or talk about the different methods that were being used to teach the math lesson? Would this be a good or a bad idea?  How would this influence the study results?

5.What if the fitness instructor allowed participants to take other herbal supplements in addition to the supplements being tested?  Would this be a good or a bad idea?  How would this influence the study results?