By Anthony M. Wanjohi
Survey research design is one of the most popular descriptive research designs used by students of research, practitioners and scholars. Surveys are broadly classified into two, namely cross-sectional and longitudinal surveys.
Cross-sectional Surveys are primarily used to determine prevalence which equals the number of cases in a population at a given point in time (Levin, 2006). Typically, a cross-sectional study involves drawing a sample of elements of the population of interest. The design is useful in describing the characteristics of a large population, makes use of large samples, thus making the results statistically significant even when analyzing multiple variables; the design also allows use of various methods of data collection such as questionnaire, structured and unstructured interviews and document analysis. It also makes use of standardized questions where reliability of the items is determined. Further, the findings of the study can be generalized (Owens, 2002).
A longitudinal study according Ployhart and Robert (2010), follows the same sample over time and makes repeated observations. With longitudinal surveys, for example, the same group of people is interviewed at regular intervals, enabling researchers to track changes over time and to relate them to variables that might explain why the changes occur. Longitudinal research designs describe patterns of change and help establish the direction and magnitude of causal relationships. Measurements are taken on each variable over two or more distinct time periods. This allows the researcher to measure change in variables over time. It is a type of observational study and is sometimes referred to as a panel study.
The longitudinal survey study has the following features: allow the analysis of duration of a particular phenomenon, enables survey researchers to get close to the kinds of causal explanations usually attainable only with experiments, permits the measurement of differences or change in a variable from one period to another [i.e., The description of patterns of change over time], facilitates the prediction of future outcomes based upon earlier factors.
The main types of longitudinal studies include rotating panel surveys [when individuals are tracked and studied], Household panel surveys [when individuals are followed and observed within their household and information is collected] and cohorts (Bryant, 2013).
Cohort Research Design: A cohort study is one type of the longitudinal survey which is conducted over a period of time involving members of a population with some commonality or similarity (Healy & Devane, 2011). Using a quantitative framework, a cohort study makes note of statistical occurrence within a specialized subgroup, united by same or similar characteristics that are relevant to the research problem being investigated, rather than studying statistical occurrence within the general population. Using a qualitative framework, cohort studies generally gather data using methods of observation.
The research designs may be as confusing as the types of research studies that exist. This guide has briefly explored the key research designs which students of research and practitioners can adopt in their studies. Fundamentally, the research design should be dictated by the type of study a researcher intends to undertake based on the issue at hand. A researcher should provide an explanation for the choice of research design chosen in a particular study. Remember, research is in the design!
Proceed to read other major types of research designs
Bryant, L. (2013). Longitudinal Studies: Essex historical learning site. Retrieved from www.historylearningsite.co.uk.
Healy, P. Devane, D. (2011). Methodological Considerations in Cohort Study Designs. Nurse Researcher, 18 : 32-36.
Owens, L.K. (2002). Introduction to Survey Research Design. SRL Fall 2002 Seminar Series. Retrieved from http://www.srl.uic.edu/seminars /Intro/introsrm.pdf
Ployhart, R. E., & Robert, J. V. (2010). Longitudinal Research: The Theory, Design, and Analysis of Change. Journal of Management, 36, 94-120.