Discuss the significance of composition and size to sampling. What effect does each have on the outcome of the study?

SUMMARY OF CHAPTERS FOR QUESTION

This week’s lesson will focus on descriptive research design, longitudinal and epidemiological designs, meta-analysis, sampling, reliability, and validity. Topics covered include simple and complex descriptive design, epidemiological and longitudinal design methods, mixed design methods, probability sampling, measurement, and content, construct, and criterion validity. Secondary analysis, big data, meta-analysis, nonprobability sampling, and consistency are also covered.

After completing this lesson, you are expected to be able to:

·Define descriptive research design.

·Relate primary and secondary analysis to meta-analysis.

·Explain epidemiological and longitudinal designs.

·Define sampling, reliability, and validity.

·Describe methods of measurement.

·Explain the process of constructing validity.

Take a moment to review the listed publications and videos below to help bring clarity and supplement your course readings as you progress through our course.

Descriptive Research

Descriptive research is a study designed to depict the participants in an accurate way. More simply put, descriptive analysis is all about describing people who take part in the survey.

There are three ways a researcher can go about doing a descriptive research project, and they are:

Observational, defined as a method of viewing and recording the participants

Case study is defined as an in-depth study of an individual or group of individuals

Survey is defined as a brief interview or discussion with an individual about a specific topic

• Descriptive Blog: The 3 Basic Types of Descriptive Research Methods
• https://psychcentral.com/blog/the-3-basic-types-of-descriptive-research-methods/
• Video: Descriptive Research Design

https://www.youtube.com/watch?v=jhPWBahCvQM

Mixed Methods Research

Mixed methods research (Extracted from the article below) is the use of quantitative and qualitative methods in a single study or series of studies. It is a new methodology that is increasingly used by health researchers, especially within health services research. There is a growing literature on the theory, design, and critical appraisal of mixed methods research. However, few papers summarize this methodological approach for health practitioners who wish to conduct or critically engage with mixed methods studies.

Article: Using Mixed Methods in Health Research

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3697857/

Mixed Methods

https://www.youtube.com/watch?v=1OaNiTlpyX8

Meta-Analysis

Meta-analysis is a statistical technique for combining data from multiple studies on a particular topic. A Meta-analysis is an analytical tool for estimating the mean and variance of underlying population effects from a collection of empirical studies addressing ostensibly the same research question. Meta?analysis has become an increasingly popular and valuable tool in psychological research, and significant review articles typically employ these methods.

Article: Meta-Analysis in Medical Research

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3049418/

Video Meta-Analysis (An Introduction)

https://www.youtube.com/watch?v=RqmgKg5jTLE

Epidemiology

According to the Centers for Disease Control, Epidemiology is the method used to find the causes of health outcomes and diseases in populations. In epidemiology, the patient is the community, and individuals are viewed collectively. By definition, epidemiology is the study (scientific, systematic, and data-driven) of the distribution (frequency, pattern) and determinants (causes, risk factors) of health-related states and events (not just diseases) in specified populations (neighborhood, school, city, state, country, global).

Article: Epidemiology is a Science of High Importance

https://www.nature.com/articles/s41467-018-04243-3.pdf

Video: Epidemiology

https://www.youtube.com/watch?v=S5XRh47T420

Longitudinal Studies

A longitudinal Study is an epidemiologic study that follows a population forward over time, evaluating the effects of one or more variables on a process. If individuals are followed, it is termed a longitudinal cohort study. If classes—e.g., age classes—are studied, it is a longitudinal cross-sectional study. Longitudinal studies are the converse (opposite) of horizontal (parallel) studies.

Article Longitudinal Studies

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4669300/

Video (A Lecture Recording): Longitudinal Studies

https://www.youtube.com/watch?v=Ioayy73PvsE

Sampling and Reliability

One valuable component of research includes data collection and the validity of your research information. Research is a serious initiative, think about what if your data, methodology or eventual outcome methods are not quite up to standard. Your sample sizes were not correct; your information was affected; you could disseminate the wrong information, thus affecting populations at large. We have an ethical responsibility to do the right thing for our perspective communities as well as our healthcare professionals. For those who choose to continue their studies at the doctoral level, research, it is methodology, its application to practice (for DNP candidates) and the generation of new knowledge (for Ph.D. candidates), will quickly discover the importance of mastering these skills or having access to available resources.

Chapter 8: Sampling

Let us explore the various types of sampling that will be involved in this module. Sampling is the process of selecting units (e.g., people, organizations) from a population of interest so that by studying the sample, we may somewhat generalize our results back to the population from which they were chosen. Please review chapter 8 in your Tappen class text.

Video: Sampling… What is sampling?

https://www.youtube.com/watch?v=Gs-gLeYuDZw

Article: Sampling in Research

http://www.indiana.edu/~educy520/sec5982/week_2/mugo02sampling.pdf

So how does one begin?

Population identification

Obtain a sampling frame

Look at a sampling frame specify (this can be done randomly or non-randomly)

Determine the sample size

Methods of sampling from a population

Simple random sampling. In this case, everyone is chosen entirely by chance, and each member of the population has an equal chance, or probability, of being selected. Please become familiar with the following concepts.

Systematic sampling.

Stratified sampling.

Clustered sampling.

Convenience sampling.

Quota sampling.

Judgment (or Purposive) Sampling.

Snowball sampling.

Chapter 9: Reliability

Class, when it comes to reliability and validity, these concepts are associated with the highest quality of measurement in your research endeavors. Chapter 9 has an emphasis on reliability, although there is mention of validity, much of this content is associated with your reading assignment in Chapter 10. However, since there is an overlap in these concepts, you will hear mention regarding the topic. I hope not to confuse anyone.

Please note that reliability is one of the most important qualities of a research tool. Think of reliability as an instrument of measure that determines the degree of consistency with which it measures the attribute for what it is supposed to measure. If a measuring tool is accurate, it is said to be reliable.

Estimation of reliability:

Stability – it is the extent to which the same results are obtained repeatedly during testing.

Test/Re-test method

Equivalence – shows the consistency of performance on different forms of the test; it is based on the correlation between performance on the different forms administered at the same time.

• Inter rater method – this is estimated by having two or more trained observers watching the same event simultaneously and independently, then recording the relevant variable.
• Intra rater method – scores are assessed by two tools by a single researcher, then the method is called the intra-rater method of calculating reliability.
• Internal consistency – this shows the consistency of performance on the different pasts of items of the test taken at ta single setting.
• Pilot study – it is the entire operation in a miniature version. It is a careful empirical checking of all phases of the study from the collection of data to their tabulation and analysis.

Summary Points:

Psychological researchers do not simply assume that their measures work. Instead, they conduct research to show that they work. If they cannot show that they work, they stop using them. You will see this while exploring the methodology section of your research.

There are two distinct criteria by which researchers evaluate their measures: reliability and validity. Reliability is consistency across time (test-retest reliability), across items (internal consistency), and across researchers (interrater reliability). Validity is the extent to which the scores represent the variable they are intended to.

• Validity is a judgment based on various types of evidence. The relevant evidence includes the measure’s reliability, whether it covers the construct of interest, and whether the scores it produces are correlated with other variables they are expected to be correlated with and not correlated with variables that are conceptually distinct.
• The reliability and validity of a measure are not established by any single study but by the pattern of results across multiple studies. The assessment of reliability and validity is an ongoing process.
• Reference
• Petty, R. E, Briñol, P., Loersch, C., & McCaslin, M. J. (2009). The need for cognition. In M. R. Leary & R. H. Hoyle (Eds.), Handbook of individual differences in social behaviour (pp. 318–329). New York, NY: Guilford Press
• For additional clarification and supplemental resources, please access the following:
• Video: Understanding Measurement Validity
• https://www.youtube.com/watch?v=kkjjZtFV9ZE

Video: Reliability and Validity of Measurement

https://www.youtube.com/watch?v=VTHWQOuEfiM

Article: Understanding Reliability and Validity in Qualitative Research

https://nsuworks.nova.edu/tqr/vol8/iss4/6/