Discuss the strengths and weaknesses of experimental designs.
When a researcher is designing a study they must take into account what experimental design will be
the most advantageous for answering their hypothesis. They must also decide which design will best
accommodate the sample and variables they wish to analyze. An experiment that has random subject
assignment will have the strongest internal validity. Though experimental designs all have independent
variables, dependent variables, and experimental units of measurement there are differences between
strengths and weakness when comparing designs. The designs are broken into two categories: signal
enhancing designs and noise-reducing designs.
Signal Enhancing Designs
Signal enhancing designs are also known as factorial designs. These designs focus on the program,
treatment and its components and whether the treatment has an effect. The strengths of the factorial
design is that it allows you to test whether the subcomponents and components have an effect. The 2x2
factorial designs strengths it’s the only design that allows researchers to test interactions between twovariables such time and setting. Additionally, factorial designs enhances signal and is efficient in its
design. Weaknesses of factorial design are its complex and require a lot of participants.
Noise-Reducing Designs
Noise-reducing designs are broken into two categories: covariance and randomized block design.
These are designs which the samples group is randomly distributed in homogenous subgroups making
the experiment repeatable. The strengths of noise reducing designs are blocking helps to compare the
treatment groups before the start of the experiment than a completely randomized design has more
power, extensively thorough experiment design and interaction between variables can be assessed.
Weaknesses of noise-reducing designs are monetary cost are high, difficult to find highly correlated
factors and variables and if poorly correlated this can lead to loss of power in the experiment.