The Purpose of Correlational Studies:
Correlational studies are used to look for relationships between variables. There are three possible results of a correlational study: a positive correlation, a negative correlation, and no correlation. The correlation coefficient is a measure of correlation strength and can range from –1.00 to +1.00.
- Positive Correlations: Both variables increase or decrease at the same time. A correlation coefficient close to +1.00 indicates a strong positive correlation.
- Negative Correlations: Indicates that as the amount of one variable increases, the other decreases (and vice versa). A correlation coefficient close to -1.00 indicates a strong negative correlation.
- No Correlation: Indicates no relationship between the two variables. A correlation coefficient of 0 indicates no correlation.
Limitations of Correlational Studies:
While correlational studies can suggest that there is a relationship between two variables, they cannot prove that one variable causes a change in another variable. In other words, correlation does not equal causation. For example, a correlational study might suggest that there is a relationship between academic success and self-esteem, but it cannot show if academic success increases or decreases self-esteem. Other variables might play a role, including social relationships, cognitive abilities, personality, socio-economic status, and myriad other factors.
Types of Correlational Studies:
1. Naturalistic Observation
Naturalistic observation involves observing and recording the variables of interest in the natural environment without interference or manipulation by the experimenter.
Advantages of Naturalistic Observation:
- Gives the experimenter the opportunity to view the variable of interest in a natural setting.
- Can offer ideas for further research.
- May be the only option if lab experimentation is not possible.
Disadvantages of Naturalistic Observation:
- Can be time consuming and expensive.
- Does not allow for scientific control of variables.
- Experimenters cannot control extraneous variables.
- Subjects may be aware of the observer and may act differently as a result.
2. The Survey Method
Survey and questionnaires are one of the most common methods used in psychological research. In this method, a random sample of participants completes a survey, test, or questionnaire that relates to the variables of interest. Random sampling is a vital part of ensuring the generalizability of the survey results.
Advantages of the Survey Method:
- It’s fast, cheap, and easy. Researchers can collect large amount of data in a relatively short amount of time.
- More flexible than some other methods.
Disadvantages of the Survey Method:
- Can be affected by an unrepresentative sample or poor survey questions.
- Participants can affect the outcome. Some participants try to please the researcher, lie to make themselves look better, or have mistaken memories.
3. Archival Research
Archival research is performed by analyzing studies conducted by other researchers or by looking at historical patient records. For example, researchers recently analyzed the records of soldiers who served in the Civil War to learn more about PTSD ("The Irritable Heart").
Advantages of Archival Research:
- The experimenter cannot introduce changes in participant behavior.
- Enormous amounts of data provide a better view of trends, relationships, and outcomes.
- Often less expensive than other study methods. Researchers can often access data through free archives or records databases.
Disadvantages of Archival Research:
- The researchers have not control over how data was collected.
- Important date may be missing from the records.
- Previous research may be unreliable.
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