Research Basics Types of Studies Types of Studies

Research Basics Types of Studies

Types of Studies Experimental Correlational Surveys & Interviews Focus Groups Observation Case Studies Literature Review Anecdotal Evidence & Testimonials

Terms to review experiment group gathered for an Experimental groupexperiment group exposed to variable Reliable-consistently measuring the same Control group-group thing that remains consistent Valid-accurately measuring what an Placebo-inactive or experiment is fake medication given attempting to measure to resemble a medication Variable-condition being changed in Sample-particular

Types of Studies Nutrient and food studies tend to be either experimental or correlational type studies.

Experimental Studies in which conditions are under the direct control of the researcher. Their purpose is to determine relationship between variables.

Experimental Studies Subjects are divided into groups (control, experimental, etc. ). Then the researcher manipulates the independent variables under highly controlled circumstances.

A fitness instructor wants to test the effectiveness of a supplements on students in her exercise class. To create similar groups, the students are assigned into 2 groups at random. Students in both groups are given a pill to take every day, but they do not know whether the pill is a placebo or the supplement. The instructor gives Group A the supplement and Group B receives the placebo. The students' fitness level is compared before and after six weeks of consuming the supplement or the placebo. No differences in performance ability were found between the two groups suggesting that the supplement was not effective.

Limitations of Experimental Studies A major limitation is that this method can only be used when it is practical and ethical for the researcher to manipulate the variables.

Limitations of Experimental Studies �A second limitation to this method is that FOOD experimental studies are usually done in the highly controlled setting of the laboratory. �These conditions are artificial and may not reflect what really happens in the less controlled and infinitely more complex real world.

Double Blind Placebo Experiments The best and most reliable form of study is the double blind placebo experiment. A treatment cannot really be said to be proven effective unless it has been tested with a Double Blind Placebo. AKA -gold standard of research

Double Blind Placebo In this type of study neither the subjects nor the researchers know who is getting a fake treatment (placebo) and who is getting the real treatment.

Double Blind Placebo Studies Individuals in the control group or the placebo group don't know whether they are getting the real treatment or the placebo…. (they are "blind") Furthermore, the researchers administering placebo and real treatment also don’t know which group is receiving which treatment Making it a "double-blind"

Double Blind Placebo The purpose of this kind of study is to eliminate the power of suggestion. This prevents the researchers from unintentionally tipping off the study participants, or unconsciously biasing their evaluation of the results.

Double Blind Placebo Studies * A placebo must be given to control for these improvements. * If the people in the treatment group fare significantly better than those in the placebo group, it is a strong indication that the treatment really works.

Co-relational Studies A co-relational study is a type of study in which two (or more) variables are measured and compared in a group of individuals without actually experimenting on them. ◦ Example: Studies have been done through survey’s; where they have found people who have a love for nature have more satisfaction with their lives. ◦ No specific experiment has been done to find out one causes the other-they just know there is a high association.

Correlational Studies Correlational studies can determine whether or not two variables “go together” — or determine the degree to which they change together, on average in the same or opposite directions.

Positive Correlation If two variables change together in the same direction, for example, if a person has a lot of money-they may buy more expensive cars, we say that the variables are positively correlated.

Negative Correlation If two variables change together in the opposite direction, such as alcohol intake and driving ability (the more alcohol one drinks, the less one is able to drive, on average, and vice versa), we say that the variables are….

Strengths of Correlation Studies The major strength of correlational studies is that they allow us to quickly discover general relationships among variables without having to experiment. Correlation can be used when it is impractical and/or unethical to experiment. Much larger samples. Cheaper

Limitations of Correlational Studies Correlation, cannot, prove causation. It only shows that two variables are related in a systematic way. It does not prove nor disprove that the relationship is a cause -and-effect relationship.

Retrospective Study A retrospective study is a study that looks backwards in time.

Retrospective Study Compares two groups of people: those with the disease or condition under study (cases) and a very similar group of people who do not have the disease or condition (controls). Researchers study the medical and lifestyle histories of the people in each group to learn what factors may be associated with the disease or condition.

Retrospective Study A study in which a search is made for a relationship between one phenomenon or condition and another that occurred in the past (e. g. , the exposure to toxic agents and the rate of occurrence of cancer in the group exposed compared with a control group not exposed).

Strengths of Retrospective Studies Retrospective studies are good for studying a disease that takes a long time to appear.

Limitations of Retrospective Studies The biggest problem in a retrospective study is that some of the information that we need may be hard to get and/or based on recall (memory). ◦ Memory is selective and can introduce all sorts of biases into a study! Using death certificates means interviewing family which could lead to inaccuracy. ◦ If the patient is alive, they may have to recall events that happened many, many years ago!

Prospective Study A prospective study looks forward in time. A group of subjects is selected and watched for a long period of time. May follow groups of individuals over time who are alike in many ways but differ by a certain characteristic (like smoking or not)

Most prospective studies are longitudinal and involve cohort groups. Remember that Longitudinal = over time Cohort = the same group of people

Example: Prospective Cohort Study For example, following female nurses (cohorts) who smoke and those who do not smoke for 40 years (longitudinal) and comparing them for rates of lung cancer and stroke.

Strengths of Prospective Studies Have less potential for bias. Less likely to have problems with recall.

Limitations of Prospective Studies A prospective study is slow. Unless you are studying a rapidly fatal disease, you have to wait years or even decades to accumulate sufficient data to draw any strong conclusions.

Naturalistic Observation If it is a naturalistic observation, the subjects or phenomena are not directly interfered with in any way. They are observed in their natural settings. In the social sciences this usually involves observing humans or animals as they go about their activities in real life settings. Ex. Yellow light

Surveys A type of study where data is collected via interviews or questionnaires. Relationships among the variables are determined from the data collected.

Strengths of Surveys also make it possible to sample a large number of subjects Helpful in collecting data on aspects of behavior that are difficult to observe directly. Less expensive than other kinds of research.

Limits of Surveys The major limitation of the survey method is that they rely on the selfreport method of data collection. Self report may lead to intentional deception, poor memory, or misunderstanding of the question can all contribute to inaccuracies in the data. –ex. census

Interviews or questionnaires commonly include an assortment of forced-choice questions (e. g. True-False) or open-ended questions (e. g. short answer essay) to which subjects are asked to respond.

Focus groups/Panels A focus group is a form of research in which a group of people are asked about their perceptions, opinions, beliefs and attitudes about a clearly defined topic.

Focus Groups/Panel Discussions Questions are asked in an interactive group setting where participants are free to talk with other group members. Composed of six to nine participants. A group facilitator keeps the discussion on track by asking a series of open-ended questions meant to stimulate discussion.

Strengths of Focus groups Relatively easy to undertake Results can be obtained in a short period of time (less than 2 hours) Social interaction in the group produces freer and more complex responses The researcher can probe for clarification and solicit greater

Limitations of Focus groups Requires highly skilled moderator Groups are often difficult to assemble Individual responses are not independent of one another Because the group is handselected, the results may not be representative of the general population.

Case Study An in-depth record of one person, family, group, or phenomenon. The hope is that learning gained from studying one case or two cases can be generalized to many others.

Case Studies In a case study, nearly every aspect of the subject’s life and history is analyzed to seek patterns and causes for behavior. Case studies are particularly useful when researchers want to get a detailed view of an individual's life or of a particular phenomena.

Case Studies Typical data collected might include biographical data, medical records, family history, observations, interviews, and the results of various psychological tests.

Limitations of Case Studies May not be representative of the general group or population. Since they are usually just a case or two. Case studies tend to be highly subjective (open to researchers opinion and bias) Behavior can only be described, not explained.

Limitations of Case Studies Case studies often rely on descriptive information provided by different people. This leaves room for important details to be left out. Also, much of the information collected is retrospective data, recollections of past events, and is therefore subject to the problems inherent to memory.

Testimonials are endorsements for products or services. They are designed to increase trust and confidence necessary to buy products. They can cause a “placebo effect” When people are desperate they may cling to these testimonials and information presented as “evidence”.

Anecdotal Evidence Unreliable evidence based on personal observations and experiences that have not been scientifically proven. Anecdotal: Hearsay or word of mouth

Testimonials & Anecdotal Evidence Testimonials are often purposely used in place of clinical or scientific evidence. and may completely ignore research or harder evidence that points to an opposite conclusion.

Problems with testimonials People mistake the placebo effect for true improvements. People may choose an ineffective treatment over an effective one and end up sicker (or even dead)! Many people who offer them are profit motivated too and don’t care about their customers.

The Major problem with Anecdotal Evidence & Testimonials Many people have made decisions that have endangered their health or well-being based solely on anecdotal evidence and/or testimonials.

Check out the scientific findings on any new product, diet, or “superfood” you are thinking about trying out.