Mary Zoulis
Professor O’Connor- Petruso
CBSE 7202T
Wiki Assignment #1
My research is a quasi-experimental design: specifically a one-group pretest-posttest
design. My participants are not randomly assigned. My participants are in the first grade class
and I have been their teacher since September. With my one group pretest-posttest design,
students will be pretested, exposed to a treatment, and then post tested to see if there was any
change.
Threats to Internal Validity
History
This is a valid threat because an unexpected event may occur during the intervention which
may influence the dependent variable. In addition, history poses a threat to a one group design
study. Furthermore, unexpected events such as a fire drill, student absences, a new student
arriving, possible emotional distress, or an unexpected illness, and even a change in weather can
influence the dependent variable.
Maturation
Since I will be conducting a read aloud to students for the three week period I will be
implementing my intervention, some students may be engaged before, during, and after the read
aloud, whereas other students may lose interest which will affect their ability to learn about
bullying.
Testing/Pre-test Sensitization
Testing will not be a threat to internal validity as each student will be given a survey before
and after intervention and not a test. Students will not be required to study for these surveys like
they would for an exam.
Instrumentation
Although I will be passing a different survey before intervention and after intervention to
the class, students may feel pressure to circle answers that are not true in order to conceal that
they have been bullied or have bullied others in the past. Hence, this will influence the validity
of my results. For the post survey, they may also circle answers which show that they have
learned something after my intervention, but in reality may be circling those answers to not show
me that they were not paying attention or did not understand a specific idea related to bullying.
Mortality
During the course of this study, some participants may move to another school causing
inflated results. Hence, this is a valid threat to internal validity.
Statistical Regression
This is a valid threat because there are only 6 students participating in the experiment,
which could produce statistically significant results that are extreme.
Differential Selection of Subjects:
This is a valid threat, as students will not be randomly assigned. Hence, participants may
have different developmental and cognitive levels at the onset of treatment.
Selection-Maturation Interaction:
This is a valid threat because students have different maturation levels, which may affect
their response to treatment.
Threats to External Validity
Ecological Validity
I do not think this poses a threat to external validity because results cannot be replicated
and therefore made generalized. Each student comes to the classroom with different bullying
experiences and understanding of what bullying is and therefore results cannot be generalized for
another population.
Pre-test Treatment
This is a valid threat because students could respond differently to the post-test
assessment since they know they were administered the pre-test previously. Students may want
to show that they have learned something about bullying when in reality they are just trying to
answer the “correct way.”
Selection-Treatment Interaction
This will not pose a threat to external validity due to my quasi experimental (one group)
design.
Specificity of Variables
This will not pose a threat to external validity because pre and post surveys will be well
thought out and organized around bullying causes, effects, and improving character as a way of
reducing bullying occurrences
Multiple Treatments
Not applicable to my research. All students will receive the same treatment for the same
amount of time and not in succession.
Treatment Diffusion
This is not a valid threat because there is only one experimental group in this study that
will be receiving treatment.
Experimenter Effects (Active Elements)
Researcher will avoid all possible bias, but this can still cause a threat to the study if it
happens unconsciously. Researcher has some knowledge about who bullies others and who have
been victimized in the classroom, but does not know to what extent the participants bully or have
been bullied.
Reactive Arrangements/Participants Effects
The Hawthorne effect can cause a potential threat if participants discover they are being
observed. During role playing, the researcher will be observing what students have learned
about bullying as a result of the intervention.
Compensatory Rivalry Effect
Although there is only one group, while role playing, students may want to outshine the
other group that is role playing because they think they are in competition with them. Hence,
this may pose a threat to external validity.
Placebo Effect
This is not a valid threat because the students will only be given treatments that are
intended to have an effect.
Novelty Effect
This may be a valid threat to external validity because this treatment has not been used
with these students before. Therefore, participants may develop a heightened interest which may
have an effect during the onset of treatment. However, this interest may wear off as time
progresses.
References
O’Connor-Petruso, S. (2013). Descriptive Statistics Threats to Validity [PowerPoint slides].
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