Quasi-Experimental Designs - Assignment Example

vi). Single-case designs or single-case research designs are used to studies that factor in individual organism variances than group designs, which emphasize on mean averages of groups (Jackson, 2013). Single-case designs are used where a test subject’s behavioral trends are variables of significance in an experiment. This research design is also used in evaluating the effect of treatments on an individual or personal attributes in applied research (Jackson, 2013). viii). A multiple-baseline research design involves the measurement of multiple persons, settings or traits before and after assignment to experimental treatment.

Treatments are administered, at different times, to ensure that changes are due to treatment and not by chance (Jackson, 2013). Reversal experimental design involves measurement of behavior or traits during a baseline periods (A), at the introduction of treatments (B), reinstatement of conditions preceding baseline period (A) and during of the reintroduction of the treatment (B) (Jackson, 2013). Question #2 Quasi-experiments are used, in empirical studies, to estimate the impact and influence of an intervention or treatment on its target sample population, and they do not use random assignment (Jackson, 2011).

Quasi-experimental designs allow a researcher to control the assignment to the treatment condition, using some criterion other than random assignment (Jackson, 2012). This is in the sense that a researcher controls the assignment to the treatment condition, and can in some cases, a researcher can lack control over the assignment to the treatment condition. Quasi-experimental designs are predisposed to quality concerns regarding internal validity because treatment and control groups, in some instances cannot be comparable at baseline levels.

This is unlike random experiments where either subjects have a chance of being assigned to the comparison or the intervention group (Jackson, 2012). The advantages of quasi-experimental designs are that they are used when randomized experimental designs are impractical and unethical. Quasi experiments are easier to prepare than ‘true experimental designs’ which require random assignment to participants or subjects (Jackson, 2012). The use of quasi-experimental designs eliminates or diminishes threats to external validity because natural environments are not susceptible to the same problems of artificiality compared to well-controlled laboratory setting.

Quasi-experimental designs allow their findings to be applied to other subjects and settings, creating a precedent where generalizations can be made about populations (Jackson, 2012). This is because this design type is considered a natural experiment, which makes its findings applicable to other settings and participants. Quasi experiments are efficient especially in longitudinal research studies, which involve longer experimental periods, and can be followed up in different environmental settings.

Quasi-experimental designs give the researcher manipulation options to choose from. This is in the sense that, in natural experiments, manipulations occur on their own accord because researchers have no control over their occurrence. The use of self-selected groups in this design type eliminates the chance of conditional and ethical concerns in the process of conducting the experiment (Jackson, 2012). Estimates or findings in quasi-experimenta