Rcts Randomized Controlled Trials (Rcts) Are Considered

RCTs Randomized controlled trials (RCTs) are considered the "gold standard" in research that attempt to identify some type of causal relationship between an independent variable and dependent measure (Kraemer, Wilson, Fairburn, & Agras, 2002). The reason for this is that the process of random assignment to treatment groups or to the groups that receive the independent variable statistically controls for all the individual differences occurring in the participants that could affect the outcome except for the variable of interest (Kraemer et al., 2002).

The control condition in an RCT allows for comparisons between the different levels of the independent variable and no intervention at all. This is particularly important in medical studies where a particular condition such as depression or some illness may change over time without any type of intervention or treatment. RCTs are not a remedy for poorly designed research methodologies and they do not reduce experimenter bias, certain expectations that the participants have, and measurement errors (Jackson, 2012).

In order to reduce experimenter bias and expectations in the participants the use of double blind RCT's, where neither the researchers nor the participants know what condition of the experiment they have been assigned to, are considered the "gold standard" (Kraemer et al., 2012). There are some drawbacks to true experimental designs that use randomized assignment (e.g., see Jackson, 2012; Kraemer et al., 2012; Simon, 2001). First, sample sizes typically need to be larger than in many types of correlational research.

Secondly, there are certain types of subject variables that cannot be randomly assigned such as gender, some type of congenital problem, etc. When looking at specific influences on what causes people to develop a specific disorder or a specific attitude one cannot randomly assigned subjects to research conditions, where they will develop some specific problems such as drug abuse, would be unethical (you cannot assign human subjects to a condition that will result in their developing a disorder or expose them to harmful conditions).

In cases where diseases such as HIV are being investigated it is not ethical to use a pure control group where people with HIV get no intervention. In these cases the new medications are compared to existing medications and there is no true control group. RCTs are not appropriate for research studies that are not looking at specific cause and effect relationships. Finally, the use of randomized assignment and blind experimental conditions only allows researchers to infer cause-and-effect relationships in the particular study conditions in which the research takes place.

RCTs do not allow researchers to generalize the effects of their findings outside of the sample of participants in the particular study in question. This brings up the question of internal and external validity of research. The internal validity of a research study describes how well the conditions in the research study control for extraneous variables that can influence the study's findings. RCTs typically have good internal validity. External validity refers to the ability of any particular research study to generalize outside the conditions of the study.

External validity depends on the how the researchers recruited the participants (the sampling method used) and how well the conditions of the research study emulate the real world conditions they are meant to be applied to (Jackson, 2012). For instance, Inal and Kelleci (2012) investigated the use of distraction to decrease procedural pain in children between the ages of six through 12 years old. The findings of the study would not generalize to adults over 21 as these two particular cohorts are quite different.

As mentioned above an RCT is a statistical control targeted at subject variables. When participants have an equal choice for being selected to any one of the experimental conditions it statistically evens out all washes out subject variables; however, it is quite possible that even a particular study that uses RCT still suffers from bias related to subject variables. For instance, many studies stratify subjects on well-known statistical compounds such as their level.