A study can be undertaken in which data are gathered just once, perhaps over a period of days or weeks or months, in order to answer a research question. Such studies are called one-shot or cross-sectional studies (see the following example). Data collection at one point in time is sufficient to answer research questions. 

Example 1: Data were collected from stock brokers between April and June of last year to study their concerns in a turbulent stock market. Data with respect to this particular research had not been collected before, nor will they be collected again for this research. 

Example 2: A drug company wanting to invest in research for a new obesity (reduction) pill conducted a survey among obese people to see how many of them would be interested in trying the new pill. This is a one-shot or cross-sectional study to assess the likely demand for the new product. 

In some cases, the researcher might want to study people or phenomena at more than one point in time in order to answer the research question. For instance, the researcher might want to study employees’ behaviour before and after a change in the top management, so as to know what effects the change accomplished. Here, because data are gathered at two different points in time, the study is not cross-sectional or of the one-shot kind, but is carried longitudinally across a period of time. Such studies, as when data on the dependent variable are gathered at two or more points in time to answer the research question, are called longitudinal studies. 

Example 1: A marketing manager is interested in tracing the pattern of sales of a particular Example product in four different regions of the country on a quarterly basis for the next two years. Since data will be collected several times to answer the same issue (tracing pattern of sales), the study falls into the longitudinal category. 

Example 2: In 2002, Sturges, Guest, Conway and Davey published the results of a two-wave longitudinal study investigating the relationship between career management and organizational commitment among graduates in the first ten years at work. Data were collected at two points in time 12 months apart. The results of this study showed that high organizational commitment predicts the practice of career management activities by graduates to further their career within the organization. On the other hand, low commitment was closely associated with behaviour aimed at furthering their career outside the organization. The results also pointed out that graduates who manage their own careers receive more career management help from their employer. This suggests that there may be the potential for employers to create a ‘virtuous circle’ of career management in which individual and organizational activities complement each other.

Different Time Points