Although cross-sectional study and longitudinal study are both observational studies, there are multiple differences in their scope, methods, advantages and limitations. Here are the list of 21 major differences between cross-sectional study and longitudinal study. They are:
| S.N. | Cross-sectional study | Longitudinal study |
| 1 | Cross-sectional studies are carried out in one specific point of time | Longitudinal studies are carried out over the period of time |
| 2 | It provides a snapshot of the situation | It provides a long-term analysis of the situation |
| 3 | Only the present situation is seen | Evolutionary characters are seen. |
| 4 | There will be no interventions | There may be interventions while conducting this study |
| 5 | In this study, participants are needed only once for the study purpose | In this study, participants are engaged throughout the study |
| 6 | Data is collected from different samples at one specific point of time | Data is collected from the same sample over the period of time |
| 7 | Individuals are studied/analyzed at one point of time | The cohort is followed up over the period of time |
| 8 | It is known as descriptive research | It is known as causal or relational research |
| 9 | The advantage of this design is that it allows researchers to compare different variables (age, sex, gender, income etc.) at single point in time | Here, only one variable is considered to conduct the study over a period of time. |
| 10 | It can provide information about the current status/what is happening at present | It can provide information about what is happening in a certain period of time |
| 11 | It does not provide information and cannot establish cause and effect relationships | It can establish and justify cause and effect relationships |
| 12 | Researchers are not able to detect developments or changes in the characteristics of the target population | Researchers are able to detect developments or changes in the characteristics of the target population at both the group and the individual level |
| 13 | These studies take relatively shorter time than longitudinal studies | These studies take longer time compared to cross-sectional studies |
| 14 | Single observation of the subject is done at a specific point of time | Several observations of same subjects are done over a period of time |
| 15 | It can compare different samples at one given point in time | It measures single group over an extended period of time |
| 16 | Economically, cross-sectional studies are cheaper and cost effective compared to longitudinal studies | Economically, longitudinal studies are expensive compared to cross-sectional studies |
| 17 | The results are not considered very strong and confident i.e. the strength of the study is less compared to longitudinal study | The results are stronger and have detailed information i.e. the strength of the study is high compared to cross-sectional study |
| 18 | Cross-sectional studies may not discover any ‘sleeper effects’ | Longitudinal studies can also help to discover ‘sleeper effects’ or connection between different events over a period of time. |
| 19 | Findings from cross-sectional studies aren’t enough to make conclusive observations about any association/significance between variables | Findings from longitudinal studies could be used to make conclusive results or associations between variables |
| 20 | Less challenging in enrolling and requires no follow up of participants | Disadvantage- challenging to enroll and follow up participants over the period of time |
| 21 | No scope for loss to follow up of participants | May also result in loss to follow up of participants |
References and For More Information:
//learning.closer.ac.uk/introduction/types-of-longitudinal-research/longitudinal-versus-cross-sectional-studies/
//www.iwh.on.ca/what-researchers-mean-by/cross-sectional-vs-longitudinal-studies
//www.questionpro.com/blog/cross-sectional-study-vs-longitudinal-study/
//www.researchgate.net/post/What_are_the_differences_between_cross-sectional_and_longitudinal_studies
//course.oeru.org/ipsy101/learning-pathways/scientific-thinking-and-research-methods/longitudinal-and-cross-sectional-research/
//www.ncbi.nlm.nih.gov/pubmed/9754134
//methods.sagepub.com/book/key-concepts-in-social-research/n30.xml
//cdn1.sph.harvard.edu/wp-content/uploads/sites/343/2013/03/explaining-discrepancies-between-longitudinal-and-cross-sectional-models.pdf
//www.surveygizmo.com/resources/blog/longitudinal-vs-cross-sectional-studies-whats-the-difference/
//www.frontiersin.org/articles/10.3389/fpsyg.2018.00945/full
//my.apa.org/apa/idm/login.seam?ERIGHTS_TARGET=https%3A%2F%2Fpsycnet.apa.org%2F
//www.verywellmind.com/what-is-a-cross-sectional-study-2794978
//www.ello.uos.de/field.php/TheoryModelMethod/TheoryModelMethodFieldWork1LongitudinalVersusCrossSectionalStudies
//bmcgeriatr.biomedcentral.com/articles/10.1186/s12877-018-0781-8
//www.iwh.on.ca/what-researchers-mean-by/cross-sectional-vs-longitudinal-studies
//futureofworking.com/11-advantages-and-disadvantages-of-longitudinal-studies/
By Indeed Editorial Team
Published December 14, 2021
Researchers use both cross-sectional and longitudinal studies for recording and interpreting data. A cross-sectional study provides observable data related to a specific point in time, while a longitudinal study helps show researchers how data evolves over time. Understanding both types of studies can help you decide which one would be the best one to use when conducting observational research. In this article, we discuss what cross-sectional and longitudinal studies are, what differences exist between the two and some examples of each.
What is a cross-sectional study?
A cross-sectional study allows researchers to compare different variables at the same point in time. Some characteristics of this type of study include:
Short duration
A cross-sectional study examines a specific issue at a single point in time, so they are relatively short. For example, a study might look at the current blood pressure rates of people with different characteristics. Rather than focusing on how their blood pressure rates came to be, the study just focuses on the present variables.
Multiple variables
A cross-sectional study allows researchers to compare different groups of subsets based on different variables. For example, perhaps the study wants to look at the blood pressure rates of smokers and non-smokers. The study might also divide smokers into groups by age. Researchers could then measure the blood pressure rates for smokers 21 to 30 years old, 31 to 40 years old and 41 to 50 years old. Along with comparing how the blood pressure rates compare between younger adult smokers and middle aged smokers, they can also see how they differ from non-smokers.
Constant environment
Variables in a cross-sectional study do not change. These studies usually measure observable data points rather than attempting to prove causation by a changing environment. The environment and lifestyles of the individuals in the study remain as they are, and the researchers simply record the data involved as is.
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What is a longitudinal study?
A longitudinal study is conducted over an extended period of time to show causation. Here are some characteristics of a longitudinal study:
Long duration
Researchers record data from the sample group over time. The circumstances of the study do not change, and the researchers do not attempt to change the habits or environment of the study's participants. Rather, they observe, record and compare data points. Sometimes researchers record the data at specific timed intervals, such as annually or every five years.
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Static sample
A longitudinal study focuses on a set amount of people and characteristics. The static nature of the sample group means that there are fewer variables to study. One of the points of a longitudinal study is to see how the data evolves over time. By using a constant sample with consistent variables, the researchers might be able to suggest how certain environmental factors affect the sample group.
Changing environment
The structure of longitudinal study means that researchers can observe changes. For example, if a longitudinal study focuses on the blood pressure rate of smokers, the study might start when the sample group was in their 20s and might end with them in their 40s. Researchers could then see how the blood pressure rates changed over the time period. If the study also had a control group of nonsmokers, they could draw further comparisons between the two groups.
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Cross-sectional vs longitudinal studies
Here is how cross-sectional studies compare to longitudinal studies:
Length
A cross-sectional study takes a relatively short time to complete as data collection occurs only once. The study examines data at a specific time and provides only a snapshot of data to researchers. By comparison, a longitudinal study can take years or even decades to complete as it requires researchers to gather data at multiple points in time.
Cost
A cross-sectional study usually costs much less than a longitudinal study. The time frame of completing the study is much shorter and less labor-intensive. By comparison, a longitudinal study might cost significantly more as it requires multi-year commitments from everyone involved.
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Sample group
Cross-sectional studies include several different sample groups and variables. The study observes data one time for its varied sample groups. By comparison, the longitudinal study repeatedly observes the same sample group or groups with the same variables.
Data
A cross-sectional study usually does not seek to find causation. Because the study collects data at one point in time, the data might not have context regarding the past behavior of those participating in the study. A longitudinal study, however, shows how the data evolves. Researchers record the data and behavior of the sample group at timed intervals, and it might be possible to draw cause-and-effect conclusions from the data.
Examples
Here are examples of both a cross-sectional and longitudinal study about social media habits:
Cross-sectional study
A cross-sectional study might examine the social media use and platform choices of different groups of people. The study could have several samples of people divided by their age and biological sex. The study might also include other factors, such as income level. The researchers might pull several conclusions from the data, such as if a certain group was more likely to use social media, which platform they were likely to be using or if people of certain income levels were more likely to use a certain type of platform.
Longitudinal study
A longitudinal study on social media use might create a sample of people aged 18-29. Researchers could record their social media habits and tendencies throughout a set number of years. At set intervals, the researchers could check in with the sample group to see how their social media use had changed. The researchers could then continue to check in with the sample group through the end of the study's duration. The data could then report how the social media habits of the individuals changed over time.