Quasi-experimental, Correlational, and Naturalistic Designs

Important factors that influence environment is controlled by the experimenter
Confident that IV causes change in DV
Rule out rival hypothesis
Not always possible
High internal validity

Participants can be influenced by a number of factors in which the researchers have little to no control
used when strong experimental designs are not possible
Use common sense and reasoning to interpret data

Used to evaluate the impact of a variable on an ongoing process

Describe the relationship between two variables

Describe an ongoing process in its natural setting

Within-subjects design
Useful when interested in the effects of an event that has happened to all of the population being studied
single-group pretest-posttest design, weak design

Several pretest and posttest measurements
Can add reversal of phenomenon to add confidence to results

Time is one of the independent variables (related to time series design)
same participants assessed over multiple time points but nothing is introduced between any of the time points
Potential confounds

Exp. group X 0₁
Non equivalent control group O1

_{Used to compare effectiveness of some program when random assignment is not possible
low internal validity - bc groups arent similar and don`t know how they differ because no pretest
Weak design}

Pretest provides baseline info
Very informative when random assignment is not possible
Used in educational research
Compare the differences between before and after scores

Both are increasing, so something else is affecting it
Maturation- could just be because one program is writing more than the other
History`- because of pretest people want to get better, so they use feedback to write better

No increase with u of r but there is an increase with u of s
Might conclude that the program is effective because of the increase
Could be because of ceiling effects - u of r might already be at the top
Regression effects towards the means

No increase in u of r but in crease in u of s started out similar
More confidence in the effectiveness of the program
Selection by maturation: no random assignment, so u of s might attract students that are stronger writers

Strongest evidence that program is working
Most confidence in program

Try to get control groups as similar as possible to experimental group
collect as much demographic info as possible
knowing how groups differ increases confidence in results