Research Methods II PDF

Research Methods II Course Instructor: Ms. Sana Khalid  Experimental and Non-Experimental Research Design Experimental Research Design  It is used to identify the cause-and-effect questions about the relationship between two variables.  Main purpose of this research design is to...

Research Methods II Course Instructor: Ms. Sana Khalid  Experimental and Non-Experimental Research Design Experimental Research Design  It is used to identify the cause-and-effect questions about the relationship between two variables.  Main purpose of this research design is to explain the relationship by determining the underlying cause.  An experimental study is conducted with rigorous control to help ensure an unambiguous demonstration of a cause-and-effect relationship.  Researcher manipulates one or more independent variables.  Random assignment is used.  Control the confounding variables to ensure high internal validity. Example  For example, are increases in exercise responsible for causing decreases in cholesterol level? To answer the question, a researcher could create two treatment conditions by changing the amount of exercise from low in one condition to high in the other. Then, one group of individuals is assigned to the low-exercise condition, and a similar group is assigned to the high-exercise condition. Cholesterol is measured for each group, and the scores in the low- exercise condition are compared with the scores in the high-exercise condition to determine whether changes in the level of exercise cause changes in cholesterol. Non- Experimental Research Design  The nonexperimental research strategy is intended to demonstrate a relationship between variables, but it does not attempt to explain the relationship. In particular, this strategy does not try to produce cause-and-effect explanations.  Does not involve manipulation of the variables.  Lacks random assignment of the participants.  Researcher has limited control over the extraneous (confounding) variables and that is why it has low internal validity. Example  A researcher would like to determine whether the verbal skills for 6-year-old girls are different from those for 6-year-old boys. (Is there a relationship between verbal skills and gender?) To answer this question, a researcher could measure verbal skills for each individual in a group of boys and in a group of girls, then compare the two sets of scores. Experimental Research Design  experiment is a systematic research study in which the investigator directly varies some factor (or factors), holds all other factors constant, and observes the results of the variation.  The factors under the control of the experimenter are called independent variables, the factors being held constant are referred to as extraneous variables, and the behaviors measured are called dependent variables. Experimental Research Design Characteristics 1. Establishing Independent Variable  Any experiment can be described as a study investigating the effect of X on Y.  The ‘‘X’’ is Woodworth’s independent variable: it is the factor of interest to the experimenter, the one that is being studied to see if it will influence behavior (the ‘‘watching violent TV’’ in the John Stuart Mill example).  It is sometimes called a ‘‘manipulated’’ factor or variable because the experimenter has complete control over it and is creating the situations that research participants will encounter in the study.  Independent variables must have a minimum of two levels. That is, at the very least, an experiment involves a comparison between two situations (or conditions).  Types of Independent Variables Situational variables refer to different features in the environment that participants might encounter. For example, in a helping behavior study, the researcher interested in studying the effect of the number of bystanders on the chances of help being offered might create a situation in which participants encounter a person in need of help. Sometimes the participant is alone with the person needing aid; at other times the participant and the victim are accompanied by a group of either three or six bystanders. In this case, the situational independent variable would be the number of potential helpers on the scene besides the participant, and the levels would be zero, three, and six bystanders.  Sometimes experimenters vary the type of task performed by subjects. One way to manipulate task variables is to give groups of participants different kinds of problems to solve.  For instance, research on the psychology of reasoning often involves giving people different kinds of logical problems to determine the kinds of errors people tend to make. Similarly, mazes can differ in the degree of complexity, different types of illusions could be presented in a perception study, and so on.  Instructional variables are manipulated by asking different groups to perform a particular task in different ways.  For example, children in a memory task who are all shown the same list of words might be given different instructions about how to memorize the list. Some might be told to form visual images of the words, others might be told to form associations between adjacent pairs of words, and still others might be told simply to repeat each word three times as it is presented.  Control Group: The term experimental group is used as a label for the first situation, in which the treatment is present. Those in the second type of condition, in which treatment is withheld, are said to be in the control group. Ideally, the participants in a control group are identical to those in the experimental group in all ways except that the control group participants do not get the experimental treatment. 2. Controlling Extraneous Variable  The second feature of the experimental method is that the researcher tries to control what are called extraneous variables. These are any variables that are not of interest to the researcher but which might influence the behavior being studied if they are not controlled properly.  As long as these are held constant, they present no danger to the study. If a researcher fails to control extraneous variables they can influence the behavior being measured in some systematic way. The result is called confounding.  A confound is any uncontrolled extraneous variable that ‘‘covaries’’ with the independent variable and could provide an alternative explanation of the results. That is, a confounding variable changes at the same time that an independent variable changes (i.e., they ‘‘covary’’) and, consequently, its effect cannot be separated from the effect of the independent variable.  Hence, when a study has a confound, the results could be due to the effects of either the confounding variable or the independent variable, or some combination of the two, and there is no way to decide among these alternatives. Confounded studies are uninterpretable. 3. Measuring Dependent Variable  The term dependent variable is used to describe those behaviors that are the measured outcomes of experiments.  If, as mentioned earlier, an experiment can be described as the effect of X on Y and ‘‘X’’ is the independent variable, then ‘‘Y’’ is the dependent variable. 4. Randomization  When random assignment is used, every person volunteering for the study has an equal chance of being placed in any of the groups being formed.  The goal of random assignment is to take individual difference factors that could influence the study and spread them evenly throughout the different groups. Types of Experimental Research Designs  Recall that any independent variable must have a minimum of two levels. At the very least, an experiment will compare condition A with condition B. Those who participate in the study might be placed in level A, level B, or both. If they receive either A or B but not both, the design is a between-subjects design, so named because the comparison of conditions A and B will be a contrast between two different groups of individuals.  On the other hand, if each participant receives both levels A and B, you could say that both levels exist within each individual; hence, this design is called a within-subjects design (or, sometimes, a repeated- measures design). Between Subject Design  A between-subjects study design, also called independent groups or between-participant design, allows researchers to assign test participants to different treatment groups.  In this design, different groups of participants are tested under different conditions, allowing the comparison of performance between these groups to determine the effect of the independent variable.  In a between-subjects design, each participant is assigned to only one level of the independent variable (treatment condition), and researchers will compare group differences between participants in these various conditions. Method  In a between-subjects design, there is usually a control group and an experimental group, with each participant experiencing one of these conditions. However, these study designs can have multiple treatment conditions, so a study with three conditions.  For example, there would be three groups of subjects, each receiving one of the three treatment conditions. To prevent bias, the participants should be randomly assigned to either the control group or one of the experimental conditions. They should not know which group they are assigned to.  A between-subjects study design aims to enable researchers to determine if one treatment condition is superior to another. Researchers will manipulate an independent variable to create at least two treatment conditions and then compare the measures of the dependent variable between groups.  They will measure whether the groups differ significantly from each other due to the different levels of the treatment variable that they experienced.  This method is called between-subjects because the differences in conditions occur between the groups of subjects. A between-subjects design is the opposite of a within-subjects design. Example  Assume a psychiatrist is looking for a new medication to treat patients with Obsessive-Compulsive Disorder (OCD). She has four potential options for medications to help patients with their OCD.  To determine which medication is going to be the most beneficial for her patients, she creates four testing groups among her population of patients.  Each group receives one of the four medications. Researchers then analyze these patients and collect data to test their anxiety levels. The psychiatrist can use this study to decide which medication is best for her patients with OCD. Advantages  Avoids carryover effect Carryover effects between conditions can threaten the internal validity of a study. A carryover effect is an effect of being tested in one condition on participants” behavior in later conditions. However, in between-subjects study designs, the participants are divided into different treatment groups, so one participant’s exposure to treatment will not affect the outcome of a subsequent condition.  Short and straightforward Scheduling the testing groups is simple, and researchers tend to be able to receive and analyze the data quickly.  Multiple variables, or multiple levels of a variable, can be tested simultaneously, and with enough testing subjects, a large number can be tested. Thus, the inquiry is broadened and extended beyond the effect of one variable (as with within-subject design).  This design saves a great deal of time, which is ideal if the results aid in a time-sensitive issue, such as healthcare. Disadvantages  A large participant pool is necessary Because each subject is assigned to only one condition, this type of design requires a large sample. Thus, these studies also require more resources and budgeting to recruit participants and administer the experiments.  Individual differences Differences between subjects within a given condition may be an explanation for results, introducing error and making the effects of an experimental condition less accurate.  It can be complex and often require a large number of participants to generate any useful and reliable data. For example, researchers testing the effectiveness of a treatment for severe depression might need two groups of twenty patients for a control and a test group. If they wanted to add another treatment to the research, they would need another group of twenty patients. The potential scale of these experiments can make between-group designs impractical due to limited resources, subjects and space.  Another major concern for between-group designs is bias. Assignment bias, observer-expectancy and subject-expectancy biases are common causes for skewed data results in between-group experiments, which can lead to false conclusions being drawn. These problems can be prevented by implementing random assignment and creating double-blind experiments whereby both the subject and experimenter are kept blind about the hypothesized effects of the experiment.  Generalization, individual variability and environmental factors. Whilst it is easy to try to select subjects of the same age, gender and background, this may lead to generalization issues, as you cannot then extrapolate the results to include wider groups. At the same time, the lack of homogeneity within a group due to individual variability may also produce unreliable results and obscure genuine patterns and trends. Environmental variables can also influence results and usually arise from poor research design. Highlight the conditions in which we cannot use the between group experimental research design? 1. Limited Participant Pool or Resources: Example: In situations where the participant pool is limited (e.g., a rare population or specialized expertise required), a within-subject design can be more efficient. Each participant contributes data to all conditions, maximizing the use of available participants. 2. Repeated Measures or Longitudinal Studies: Example: In a study tracking changes over time, such as the progression of a medical condition or the impact of an intervention on participants' attitudes, a within-subject design is often necessary. It allows researchers to examine changes within the same participants over multiple measurement points. 4. Sequence or order effects (i) practice effect: an improvement in performance on a task due to repetition, for example, because of familiarity with the task (ii) fatigue effect: a decrease in performance of a task due to repetition, for example, because of boredom or tiredness. Repeated/ Within Subject Design A within-subjects design is a type of experimental design in which all participants are exposed to every treatment or condition. It is also known as a repeated measures design. The term "treatment" describes the different levels of the independent variable, the variable that the experimenter controls. In other words, all of the subjects in the study are treated with the critical variable in question. Procedure 1. Define Research Question and Hypotheses:  Clearly articulate the research question and formulate hypotheses that specify the expected effects of the independent variable on the dependent variable. 2. Select Participants:  Recruit a sample of participants who meet the inclusion criteria for your study and have specific characteristics. 3. Random Assignment or Counterbalancing:  If applicable, randomly assign participants to different orders of conditions to control for order effects.  Use counterbalancing methods to ensure each condition appears in each position of the sequence an equal number of times. 4. Pretest (if applicable):  Conduct a pretest or baseline measurement of the dependent variable if needed to establish a baseline before the experimental manipulations. 5. Administer Conditions:  Expose each participant to all levels or conditions of the independent variable. Randomize or counterbalance the order in which participants experience the conditions to control for order effects. 6. Control for Carryover Effects:  Implement a washout period or control procedure if there is a concern about carryover effects (e.g., a break between conditions to minimize the impact of the previous condition). 7. Measure Dependent Variable:  Collect data on the dependent variable for each participant in each condition and ensure that measurement tools are reliable and valid. 8. Data Analysis:  Use appropriate statistical analyses to compare the performance or responses of participants across different conditions. 9. Interpret Results:  Examine the results to determine whether there are statistically significant differences between conditions. 10. Draw Conclusions:  Based on the analysis and interpretation, draw conclusions regarding the effects of the independent variable on the dependent variable. Discuss the implications of the findings and any limitations of the study. Example Advantages  Uses a Smaller Sample Size It does not require a large pool of participants. A similar experiment in a between-subject design requires twice as many participants as a within- subject design when two or more groups of participants are tested with different factors.  Reduces Errors Caused by Individual Differences It can help reduce errors associated with individual differences. In a between-subject design where individuals are randomly assigned to the independent variable or treatment, there is still a possibility that there may be fundamental differences between the groups that could impact the experiment's results. Each participant serves as their own baseline. Assignment 1 1. Briefly explain an experimental research design. 2. Briefly explain and highlight at least 4 factors that differentiate the between and within group experimental research design. 3. Give example of each research design (Steps/ Procedure). The assignment should be Handwritten. Make a proper title page! NO COPY PASTING Try to use different examples compared to the one we used in class. (no negative marking on this but try to use a different example  ) Submission Date: 1st October, 2024 Group Presentations  Select a Research Article (PDF)  The research article should be on experimental research design (between or within).  Highlight all the headings and present the article in your own words.  Add your own perspective to the article.  Make an appropriate ppt.  Make a word file using appropriate headings and APA format. Ensure to select write whole material in your own word. This will be considered as your second assignment. Topic Approval by 1st Oct Assignment 2 by 15th Oct Presentations will start from 8th Oct