Describe blocking and stratification in experimental study designs. What do they do? How are they used? Give an original example of each; find your example of each from a source other than your textbook.
Your response must be at least 200 words in length.
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Experimental study designs are used to evaluate the effectiveness of a particular intervention or treatment method in comparison to a control group. Blocking and stratification are two methods used in the experimental study designs to ensure that the groups being compared are similar in their characteristics. This response will explain blocking and stratification and provide original examples for each.
Blocking ensures that experimental groups are not completely random and are based on specific criteria. This method is often used in clinical trials to match participants’ age, gender, and other relevant variables such as body mass index, medical history, and baseline severity of the condition. Blocking helps to ensure that the differences in the outcomes of interest among the groups are because of the intervention being tested and not the result of differences in the characteristics of the groups.
For example, in a study to assess the effectiveness of a new drug intervention to treat a particular type of cancer, participants can be grouped based on age, gender, and cancer stage. This would ensure that if the new drug intervention worked, it could relate to all groups equally.
Stratification, on the other hand, is a method used to break a population into subgroups based on relevant variables. This method helps to highlight differences in the outcomes of interest among the subgroups within the population being studied. Stratification is used to identify factors that impact the effectiveness of the intervention being tested.
For example, consider a study examining the effectiveness of a weight loss program. Stratification can be done on the basis of subgroups such as age, gender, weight, or BMI. The study can then compare the results across different subgroups to identify which subgroup responded best to the intervention, and whether the intervention was more effective for one subgroup compared to another.
Blocking and stratification are important tools in experimental study designs. They help to ensure that the groups being compared in a study are similar in their characteristics, thereby allowing the study to evaluate the intervention being tested accurately. By avoiding confounding variables, blocking and stratification allow researchers to identify subgroups that may respond better to an intervention than others.