There are two classes of factors that jeopardize the validity of research findings they are internal and external. Internal validity is the extent to which a test measures what it claims to measure. External validity on the other hand, is the extent to which the results of a research study can be generalized to other groups, times, and settings (Trochim and Donnelly, 2008). Internal validity is threatened whenever there exists the possibility that alternative causes, other than the independent variable, are responsible for the effect. There are a number of possible threats to internal validity, the seven most commonly referenced threats include history, maturation, testing, instrumentation, mortality, regression, and selection. History refers to specific events, in addition to the treatment, that occur between the first and second measurement. The longer the interval between the pretest and posttest, the more viable this threat becomes. Maturation pertains to changes in physical, intellectual, or emotional characteristics, that occur naturally over time, that influence the results of a research study. For example, in longitudinal studies, individuals grow older and become more sophisticated. Testing, refers to the effects of taking a test upon performance on a second testing. Exposure to the pretest may influence performance on a posttest. The shorter the interval between the pretest and posttest, the more viable this threat becomes. Instrumentation is concerned with changes in the way a test or other measuring instrument is calibrated that could account for results of a research study. This threat is most likely to occur from an unreliable measuring instrument (Creswell, 2009). Mortality refers to the differential loss of indiv... ... middle of paper ... ...4. Choosing an appropriate research design can help control most other threats to internal validity. In general, threats to the external validity of a study can be minimized if the researcher has taken steps to insure that the sample, the setting, and the context are representative of the population, setting, and context to which the results are intended to be generalized (Trochim and Donnelly, 2008). Works Cited Creswell, J. W. (2009). Research design: Qualitative, quantitative, and mixed methods approaches (3rd ed.). Thousand Oaks, California: SAGE Publications, Inc. Fraenkel, J. R., & Wallen, N. E. (2006). How to design and evaluate research in education (6th ed.). New York, New York: McGraw-Hill Humanities/Social Sciences/Languages. Trochim, W. M.K., & Donnelly, J. P. (2008). The research methods knowledge base (3rd ed.). Mason, Ohio: Cengage Learning.
Rugg, G., & Petre, M. (2007). A gentle guide to research methods. Maidenhead: McGraw-Hill/Open University Press.
Gay, L.R., Mills, G. E., & Airasian, P. W. (2009) Educational research: Competencies foranalysis and applications. (9th. Ed.) Upper Saddle River, NJ: Prentice-Hall, Inc. ISBN-10: 0135035015
The internal validity test is very useful in expounding whether the empirical findings match with the main research questions of such a study or not; Yin (1994, P.106). Within this study, the researcher has conducted interviews. The respondent also gave her the chance to ask follow-up questions when it is necessary for her. All these facts have given her the ability to fulfil and to answer her main research question.
I found it very interesting when talking about experimental research how important validity is. There were two types internal validity and external validity. Internal was more about manipulation/controlling and removing any influence of extraneous variables. By doing so the goal is to be assured that any observed differences between groups in the study is attributed only be differences in the independent variable (e.g., treatment, intervention, and instruction) and no other factors. So, my understanding of this concept is basically understanding and verifying that the research was done right. I was wondering if anyone else got the same conclusion and if there are any other important parts to my understanding of internal validity that I am
...nclude Mono-Operation bias, according to Trochim & Donnelly (2008), which is a threat to construct validity that happens when there is a problem with your operationalization of your independent variable versus the construct on which it was based. Another design threat is that of the Mono-Method bias and this threat to construct validity refers to the use of only one method of measurement i.e. (you can’t provide proof that you are measuring what you say you are measuring) (Trochim & Donnelly, 2008). In addition, and according to Trochim & Donnelly (2008), a threat to construct validity is that of Interaction of Different Treatments, which means that experiences outside of those being controlled by your experiment effect the outcome of the study. An additional threat to construct validity that is related to design is Interaction of Testing and Treatment, which is
Research findings are considered reliable if they are consistent over a period of time and they accurately represent the total population under evaluation or study (McMillan, 2016; Golafshani, 2013). Moreover, the findings of a research study are considered reliable if they can be reproduced using similar methodology. In this regard, replication and consistency are the two characteristics that determine the reliability of any given research tool or test. Validity establishes if the research study actually measures what it was initially intended to measure (McMillan, 2016). In this regard, validity of a research is determined by how accurate the measurement tool is in measuring what it was intended to establish. Therefore, the quality of research is determined by its reliability and validity. The validity and reliability of any
Another threat to internal validity that may arise from this study by Yuan et al. (2009) is that of differential selection. This is where the study investigators are more likely to assign participants that fit a particular description to a particular group. For example it may be thought that those who were seen to be less fit were assigned to the intervention group in order to see if the intervention had any effect on this. This creates a variation in the groups that is much to the extreme (Sireci, 2007).
The four different methods of measuring validity are content validity, evidence of validity from contrasting groups, evidence of validity from convergence, and evidence of validity from convergence (Grove et al., 2015, p. 289). Content validity is a measurement of how all the elements of a test are relevant and represent the phenomenon being measured. Evidence of validity from contrasting groups examines how well an instrument correlates in the opposite direction in already established groups (Westen & Rosenthal, 2003). Evidence of validity from convergence measures how the results from a relatively new tool compares in a positive relation to the results from an established tool. Lastly, evidence of validity from divergence measures how the results of a relatively new tool compare in a negative relation to the results of an established tool that measures an opposite phenomenon (Grove et al., 2015, p. 291). Validity of an instrument is paramount in determining how the research relates to the concept that is under
Marshall, C, Rossman, Gretchen B, (2006). Designing qualitative research, 4th edition, Thousand Oaks, California: Sage Publications.
Now within the rest of this paper you will be finding a few different things getting discussed. Staring it off we will be discussing the articles that we have found to make our arguments and hypotheses. After wrapping up the literature reviews we will be discussing the hypotheses thus continuing onto our variables and indicators. Once we discuss our hypotheses we will be moving onto the research design. The research design will have our general issues, sampling, and methods.
A researcher uses an experiment to scientifically test out a hypothesis. In an experiment there are many different factors that are involved. There is the independent variable, which is the cause, it is the one that is being manipulated, and the dependent variable, which is the effect, is the response. When conducting a experiment it is important to make sure that the only thing than can affect the dependent variable is the independent variable. This is known as internal validity. Using random assignment to separate the participants into groups helps eliminate any outside factors, and creates an equal chance for all participants to be apart of the experimental conditions. There are many pros and cons to this type of method. The experimental method creates a strong control of the variables involved in the experiment, which allows an easier determination on cause and effect. If needed, it is fairly easy to replicate an experiment and is less time consuming than other research methods. However there are many downfalls as well. When conducting an experiment the setting of where the experiment is taking place is more artificial which may cause certain behaviors that wouldn’t occur in real life. This is known as external validity, which is the measure of how much the results of a study can be generalized and used in different situations, and people. To improve external validity cover stories are created when conducting experiments so the participants are not aware of what is really going on, or experiments are done in a natural setting as opposed to in a laboratory. However, this creates less control over confounding variables that can affect the experiment, which can create bias results (Aronson,
An important part of an experiment is random assignment. If the participants for the study are randomly assigned to create two groups, and the researcher has enough participants in the study to have the desired “probabilistic equivalence” (Trochim & Donnelly, 2008, p. 187) then the researcher will feel a sense of confidence that the study will have internal validity in order to assess whether or not the treatment caused the outcome hypothesized. Well-c...
For example, if we administer a measure of depression to a sample of participants all diagnosed with Major Depressive Disorder, the reliability of those scores does not apply if we administer this instrument to the population at large. For the reliability coefficient to be relevant to a certain population, the population needs to be similar to the sample that was used to assess the reliability initially.
...n experimental design with the proper adjustments to reduce the threats caused by participants, treatments, and procedures (Creswell, 2008). With a significant decrease of threats, a researcher may therefore strongly support the relationship between the variables without much ambiguity. Internal validity is important in any experiment and given that various factors threaten it in all forms of experimental designs, addressing the threats should be a priority during the design of research. If we are going to make a difference in the field of education, as researchers we need internally valid research to support future research and drive educational reform in an attempt to better the education of our children.
Creswell, J. W. (2014). Research design: qualitative, quantitative, and mixed methods approaches, 3rd Edition. Thousand Oaks: Sage Publications.