Internal validity deals with how well an experiment has been carried out, more specifically by avoiding the effects of more than one independent variable. For an experiment to have higher internal validity, it must have fewer chances for other independent variables affecting the experiment. Internal validity focuses on the degree to which the design of the study can be controlled. Internal validity is determined by exerting the degree of control over potential extraneous variables. It is necessary to control these potentially confounding variables since it helps to reduce the possibility for another explanation for treatment effects to emerge as an alternative and also provides much confidence that the independent variable affects the dependent …show more content…
These external factors are not linked to the study and therefore interfere with the overall results of the study and the final conclusions (Rubin & Babbie, 2009). There are several examples that can illustrate history as a threat to internal validity. For example, in a study to determine the effects of alcohol on judgment, participants took part in a short test during a sober state and when drunk. The participants did well when sober and poorly performed when drunk. However, they also mixed alcohol with cigarettes and other with pills which made it difficult for the researcher to conclude that the alcohol mainly influenced their score. The consumption of other drugs apart from alcohol can be regarded as external independent variables and since they have similar effects on an individual, it would be difficult to ignore them during the …show more content…
This type of threat to internal validity is very tricky and often proves difficult for researchers to avoid or handle the threat. Regression to mean occurs whenever a researcher has a sample from a population that is non-random and two measures which are imperfectly correlated (Jackson, 2012). For example, in a study to improve the performance of students in science, students who poorly performed in science were assigned to a control group and treatment group. The treatment group received special tutoring whereas the control group was involved in normal studies. During the pre-test, students from the treatment group felt more confident and performed well in the test. However, during the post-test, they felt less confident and poorly performed which resulted in little change in their mean score. The control group, however, felt less confident on the pre-test and failed but improved slightly during the post-test and this resulted in an increase in the mean. In this study, the researcher selected the two groups based on their performance. The researcher assumed that the treatment group would perform better during the post-test compared to the pre-test. However, the fact that the treatment group did
If a study is confounded, the researcher is not absolutely certain that changes in the dependent variable were caused by the manipulation of the independent variable, or some other uncontrolled variable. In a non-equivalent control group post-test only design, any differences observed between the two classes may be due to the non-equivalence of the groups and not to the injection of quizzes. No pre-test measures were given to establish equivalence.
Wilkes, E, Gray, D, Saggesr, S, Casey, W & Stearne, A 2010, ‘Substance Misuse and Mental Health
drug primarily is considered a highly addictive drug of choice. The other drug that John tes...
Drugs and Behavior, Rebecca Schilit and Edith Lisansky Gomberg, Page 62, SAGE Publications, Inc.- 1991
The multi-causal model of drug abuse takes into account social and individual causes of addiction, both distant and immediate, that lead to a disposition to using drugs, drug use and the social and individual consequences. Why a person becomes addicted to drugs or alcohol is different for everyone. Some are genetically predisposed, some learn it from their environment (i.e. family or friends), and still others use it to avoid a trauma they have experienced. The case history describes a client that had both social and individual causes for her alcohol use and subsequent dependence.
Liehr, P, Marcus, M, Carroll, D, Granmayeh, K L, Cron, S, Pennebaker, J ;( Apr-Jun 2010). Substance Abuse; Vol. 31 (2); 79-85. Doi: 10.1080/08897071003641271
The sampling procedures that can be utilized in evaluation research is vast. The selected sampling procedure is important in the consideration of external validity. External validity generalizes the findings to individuals in the study sample with characteristics that are alike (DiClemente et al., 2013). Although, not all research studies will require a sampling procedure that would deliver an external validity.
... discussing whether either environmental or biological factors propose a more significant influence regarding substance abuse, it is clear that biological factors are significantly more influential.
Internal validity, unlike external and construct validity, deals with causal relationships. In other words, the question is whether any additional research that is found is actually associated with the study that is being conducted. The question, again, is whether we can be confident that the outcome of the study is a result of the experiment itself. What this means is that internal validity is the extent to which a change in a given variable is caused by the change in another variable.
Longitudinal design validity is also dependent upon using set time intervals that make sense with the research being performed. This study does not say explicitly express how intervals for MI instruction were chosen. Furthermore, the study does not explain why or how intervals for pre and post assessments were decided. This is important because past research may have told how long it takes for MI to be successful and at what intervals it needs to be performed in order to yield the best outcomes for participants. This data may have changed the length of the study or the time intervals and potentially changed results.
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,
Out of the eight areas within the test, the participants that went through the mental skills training scored higher on six of them. Physical and psychological self-confidence were both reported to be higher for the members of the mental skills training, proving hypothesis 2 right. Finally, when divided into gender and age groups, hypothesis 3 was also proven right. To be clear, they weren’t separated into gender and age groups while doing the research. Only after they got the results, they separated the scores into gender and age groups.
Scannapreco, M., Connell-Carrick, K., et.al (2007). Substance-Use and Misuse. Vol.42, Issue 10 pg.1545-1553. Retrieved February 14th, 2011 from http://web.ebscohost.com.ezproxy.liberty.edu
With the use of drugs being such a controversial issue in today’s society we felt as a group it was important to further explore this issue. As we possess a high interest in how drugs affect a number of social groups. These groups of course range from young teens to high-class older individuals who will have different reasons and different acceptable standards of behaviour.
The use of drugs is a controversial topic in society today. In general, addicts show a direct link between taking drugs and suffering from their effects. People abuse drugs for a wide variety of reasons. In most cases, the use of drugs will serve a type of purpose or will give some kind of reward. These reasons for use will differ with different kinds of drugs. Various reasons for using the substance can be pain relief, depression, anxiety and weariness, acceptance into a peer group, religion, and much more. Although reasons for using may vary for each individual, it is known by all that consequences of the abuse do exist. It is only further down the line when the effects of using can be seen.