Cross-Sectional Research Method: How Does It Work?

Advantages and Challenges

Cross-sectional studies
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A cross-sectional study involves looking at people who differ on one key characteristic at one specific point in time. The data is collected at the same time from people who are similar on other characteristics but different on a key factor of interest such as age, income levels, or geographic location. Participants are usually separated into groups known as cohorts. For example, researchers might create cohorts of participants who are in their 20s, 30s, and 40s.

How and When Cross-Sectional Studies Are Used

This type of study uses different groups of people who differ in the variable of interest but who share other characteristics such as socioeconomic status, educational background, and ethnicity. Cross-sectional studies are often used in developmental psychology, but this method is also utilized in many other areas including social science and education.

For example, researchers studying developmental psychology might select groups of people who are remarkably similar in most areas but differ only in age. By doing this, any differences between groups can presumably be attributed to age differences rather than to other variables.

Cross-sectional studies are observational in nature and are known as descriptive research, not causal or relational, meaning that you can't use them to determine the cause of something, such as a disease. Researchers record the information that is present in a population, but they do not manipulate variables.

This type of research can be used to describe characteristics that exist in a community, but not to determine cause-and-effect relationships between different variables. This method is often used to make inferences about possible relationships or to gather preliminary data to support further research and experimentation.

Defining Characteristics of Cross-Sectional Studies

Some of the key characteristics of a cross-sectional study include:

  • The study takes place at a single point in time
  • It does not involve manipulating variables
  • It allows researchers to look at numerous characteristics at once (age, income, gender)
  • It's often used to look at the prevailing characteristics in a given population

Think of a cross-sectional study as a snapshot of a particular group of people at a given point in time. Unlike longitudinal studies that look at a group of people over an extended period, cross-sectional studies are used to describe what is happening at the present moment.

This type of research is frequently used to determine the prevailing characteristics in a population at a certain point in time. For example, a cross-sectional study might be used to determine if exposure to specific risk factors might correlate with particular outcomes.

A researcher might collect cross-sectional data on past smoking habits and current diagnoses of lung cancer, for example. While this type of study cannot demonstrate cause-and-effect, it can provide a quick look at correlations that may exist at a particular point.

Advantages of Cross-Sectional Studies

Some of the advantages of cross-sectional studies include:

  • They're inexpensive and fast. Cross-sectional studies are usually relatively inexpensive and allow researchers to collect a great deal of information quite quickly. Data is often obtained using self-report surveys and researchers are then able to amass large amounts of information from a large pool of participants.
  • They allow different variables. Researchers can collect data on some different variables to see how differences in sex, age, educational status, and income might correlate with the critical variable of interest.
  • They pave the way for further study. While cross-sectional studies cannot be used to determine causal relationships, they can provide a useful springboard to further research. When looking at a public health issue, such as whether a particular behavior might be linked to a particular illness, researchers might utilize a cross-sectional study to look for clues that will serve as a useful tool to guide further experimental studies. For example, researchers might be interested in learning how exercise influences cognitive health as people age. They might collect data from different age groups on how much exercise they get and how well they perform on cognitive tests. Performing such a study can give researchers clues about the types of exercise that might be the most beneficial to cognitive health and inspire further experimental research on the subject.

    Challenges of Cross-Sectional Studies

    Some of the potential challenges of cross-sectional studies include:

    • Finding specific participants: While the design sounds relatively straightforward, finding participants who are very similar except in one specific variable can be difficult. Cross-sectional studies generally require a large number of participants, so it's more likely that there will be small differences among participants. While such differences might seem minor, they can influence the study's findings.
    • Cohort differences: Groups can be affected by cohort differences that arise from the particular experiences of a unique group of people. Individuals born during the same period may share important historical experiences, but people in that group who are born in a given geographic region may share experiences limited solely to their physical location. Individuals who were alive during the invasion of Pearl Harbor, Vietnam, or 9/11 might have shared experiences that make them different from other age groups, for example.

    Cross-Sectional vs. Longitudinal Studies

    This type of research differs from longitudinal studies in that cross-sectional studies are designed to look at a variable at a particular point in time. Longitudinal studies involve taking multiple measures over an extended period.

    As you might imagine, longitudinal studies tend to require more resources and are often more expensive than cross-sectional resources. They are also more likely to be influenced by what is known as selective attrition, which means that some individuals are simply more likely to drop out of a study than others, which can influence the validity of the study.

    One of the advantages of cross-sectional studies is that since data is collected all at once, it's less likely that participants will quit the study before data is fully collected.