Comparing and Contrasting External and Internal Validity, Essay Example

The quality of internal validity is reliant on the precision of the results.  Consequently, in the event that the sample does not compute by the random selectionparadigms, the internalvaliditycould beinfluenced.  This is attributed to the characteristic of internal validity being reliant on the methods of data collection.  The external validityincorporates the ideas of generalization in order to determine the influences of a more expansive population (Anderson et al., 2008).  As a result, the external validity is reliant on the data collection paradigms in a similar manner as the internal validity.

There are distinctions between the facets of internal and external validity.  The internal validity usually is attributed to the research study in the absence of other research components.  On the contrary, the external validity reviews the circumstances, when the outcomes of the research study could be placed into a wider context.  The process of generalization also operates with the assistance of external validity (Goodwin, 2009).  Thais correlation could be better visualized as anexample.  In the case of when researchers apply an empirical study with the objective of reviewing a drug, the pharmaceutical organization cannot apply the test population as being composed from the target population.

It could be assumed that the research question is: identifying the influence of changes on the lifestyle of members of the Hispanicpopulation.  Consequently, with regards to the research question, the external validity could become a subject ofprimaryconcern due to the attribute of the question being directed toward the entire group of the Hispanic population instead of an indusial or a specific group.

In the event that the research question were to state: identifying the effect of the changes on the ecology in the lifestyle of members of the Hispanic teenage population, I the generalization and the simplification of the results would be very difficult to relate to the entire population of the Hispanic community.  As a result of this situation, the internalvalidity is a main concern due to the attribute that in its absence, the outcomes of the study would not be successful (Anderson et al., 2008).

In order to make strong assertions with regards to applicability of the results that are directed toward a targeted population, the researcher should apply the random sampling methods in addition to cluster sampling and systematic samples for the collection of information from the targeted population (Goodwin, 2009).  Thistechnique serves an important function in the generalization of the study results due to the sampling process being founded on probability that is inclusive of a more elevated response index.  The higher response index enables the researchers to utilize the outcomes of the study in a more comprehensivemanner.

Comparing and Contrasting the Characteristics of Random Assignment and Random Selection

The random assignment and the random selection are terms that are correlated. The random assignment provides detail with regards to the research procedures that are applied in recruiting and assigning the respondents from the distinct groups of the population (Ary et al., 2013).The random selection provides details with regards to the procedures that the researchers could apply in order to extract the samples from the entire population that is correlated to the research study.  In the case of a researcher recruiting fifty respondents from a population of five hundred with the assistance of a random sample, this would be described as random selection.  In the event that the researcher recruits fifty respondents for a new treatment intervention instead of the remaining four hundred and fifty people, this would be detailed as random assignment.

In certain contexts, random selection is not applied by the researcher in order to choose the population.  In the case of some of the respondents are selected for a completely different treatment the random selection would not be applicable. However, in this circumstance, the random assignment would be applicable. There are slight distinctions between random assignment and random selection. Random selection is reliant on the sampling procedure and is correlated with the external validity of the outcomes of the study (Le Roy, 2013). The random assignment is correlated with the internal validity of the results.

Sample Size and the Probability of a Statistical Significance

In the perspective of statistics, significance is a term that is applied in order to describe statistical qualities. The significance assists in ensuring the distinctions and the correlation that occur within two groups. In a study, it could be said that there are fifty people that are chosen for a review and the validity of the review would be determined on the grounds of the categories of male and female. The male rating is one hundred and the female rating is ninety eight. The t- test demonstrates the difference in the statistical significance as being equivalent to 0.001. Simultaneously, there is not a substantial difference between the values of ninety eight and one hundred. The outcome details that there are slight discrepancies between the groups that would not have the potential of negatively impacting the results of the study (Le Roy, 2013).

Consequently, it could be stated that the size of the sample drastically influences the results of the study, considering that the study is performed for any reason with any population.  There may be some errors that may be derived from the sample size.  In the event of a minimalsample size, the situation could influence the potential of the statistical significance due to the characteristic that the potential errors might not be encountered.  This would have the effect of influencing the results of the study.  In theevent of working with a larger population, the errorwould be minimized(LeRoy, 2013).

There is a correlation between the sample size and the probability of incurring a statistical significance between the qualities of the two groups. This is attributed to the premise that in working with a large sample size, the distinct categories of probability that include the type I and the type II errors are encountered.  The qualities of working  with a larger sample size also reduces the risk of incurring a type I and type II error, in the event that the study is conducted with care. Simultaneously, the large sample demonstrates the reasoning for the clinicians to enhance the statistical significance s parameters of the results.  As a result, it could be delineated that increasing the sample size enhances the probability of encountering a statistically significant correlation.  The probability is increased due to the larger sample size being representative of the qualities of the population (Kelley, 2013).

Probability Sampling and Non- Probability Sampling

In probability sampling, the method is applied in order to make choices with the assistance of a comprehensive random process. The sampling method of probability sampling is implemented in order to ensure that there are distinctions within the elements of the sample. This process ensures that the sample has been selected totally at random (Gray, 2009). The primary benefit of the probability sampling method is that it is based on equity.  This is due to the quality that it details that every respondent has been delegated the same opportunities prior to collecting the sample. As a result, it also enhances the validity of the results of the study. The probability sampling method is very effective with respects to sampling smallerpopulations.  In providing that each of the respondents has the same opportunity prior to gathering the samples, it demonstrates that the sample population could be without bias (Gray, 2009; LeRoy, 2013).

Disadvantages of the Probability Sampling Methods

The probability sampling method is reliant on the respondents who are selected. The research could experience error that is attributed to the respondents’’ dishonesty. This has the potential of creating flaws in the research that could influence the equity of the research. The probabilitysampling method has the requirement of being time intensive. In the event of a large sample group, the sampling process would require substantialpatience and time (Gray, 2009; LeRoy, 2013).

Non-Probability Sampling

The non-probability sampling method is distinct from the probability sampling method. This is attributed to the premise that in the non-probabilitysampling method the sample could be collected systematically.  The non-probability sampling method is also effective for small sample population. The following are some of the benefits and the disadvantages of the non- probability sampling method (Gray, 2009; LeRoy, 2013).

 Benefits

The non-probabilitysampling method is more effectivedue to the quality of assisting the clinician to direct the attention of the research towards a particular group of people (Gray, 2009; LeRoy, 2013).

Disadvantages

The primary disadvantage of the non-probability sampling method is the characteristic of bias. The bias is attributed to the premise that when respondents are selected from similargroups, their perspective and qualities could not be representative of theentire population (Gray, 2009; LeRoy, 2013).

Conclusion

The qualities ofinternal and external validity are important characteristics in the application of research methodology. Internal validity is reliant on the precision of the outcome; external validity includes the idea of generalization in order to comprehend the influences of a larger population. Random selection is reliant on internal validity.  Random assignment is reliant on external validity.  Non probability sampling is more effective for smaller populations. Probability sampling is more effective for larger sample populations.

References

Anderson, D, Sweeney, D. and Williams, T. (2008). Statistics for business and economics (10^th edition)..Belmont, CA: Cengage Learning.

Ary, D., Jacobs, L., Gorensen, C., and Walker, D. (2013). Introduction to research in education. Belmont, CA: Wadsworth Cengage Learning.

Gray. D. E. (2009). Doing research in the real world. London, UK: SAGE Publications.

Goodwin, C. J. (2009). Research methods in psychology: Methods and design. Hoboken, NJ: John Wiley and Sons, Inc.

Kelley, K. (2013). Effect size and sample size planning: The qualitative handbook of quantitative methods, Vol. I: Foundations. New York: Oxford University Press.

LeRoy, M. (2012). Research methods in political science. Belmont, CA: Wadsworth Cengage Learning.