Data processing

Appropriate statistical analysis should be done for each assessed parameter in order to detect differences between treatments and among days, in particular before and after pesticide application (see Pirk et al., 2013). The magnitude and the duration of the effects should always be detected for following parameters:

- bee mortality and behaviour deviance (see Table 1),

- strength of the colony and honey production (Delaplane et al., 2013b),

- bee activity (Scheiner et al., 2013).

Moreover, an analysis of the statistical power to detect a certain magnitude of effect should be provided in the test (Cresswell, 2011). In fact, the hazard of a pesticide should be defined in terms of magnitude and of temporal scale. For instance, in the treated fields, the bee mortality is increased x times compared with the control for y days. This information can be of use to the risk manager for mitigation actions (see section 8.4.4.).