Analysing trends

Several methods can be used to understand whether there are changes in trends. These include the following.

  • Pre and post studies
    Pre and post studies assess changes as a result of an intervention. Measures are taken both before and after the intervention in an effort to understand whether there has been a change.
  • For example, tracking behaviour over time, both before and after the compliance strategies are implemented, can help you to understand whether there has been a change in behaviour that corresponds with the implementation of the strategies. But it will not tell you whether the strategies caused that change.
  • Longitudinal studies
    A longitudinal study involves repeated observations of a specific set of participants over a period of time. It allows you to measure key variables at different points in time. The same data is collected from the same participants at regular intervals. Longitudinal studies are particularly useful for understanding the long-term effects of your strategies.
  • When choosing your sample for a longitudinal study, you must consider the effect of churn on the sample size. Churn is the number of people who move in and out of a particular group at any given time. If your population has a high churn rate, you are likely to lose a significant number of participants along the way. Increasing your sample size to allow for natural attrition of the participants over time is one way to overcome this.
  • Measuring against standards
    A standard is a reference point against which compliance behaviour or community confidence can be measured - it sets a required level of quality or performance that indicates quality or success.
  • For example, measuring behaviour against a standard allows you to see whether behaviour is coming back into line with acceptable standards (see figure 4).

Fig_4 comparing agianst a standard

    Last modified: 13 Jan 2015QC 25789