Adding a Treatment

Treatments provide a description of a study’s treatments. Any specific information such as rate of fertilizer application should be recorded in the managements table. In general, managements are recorded when Yield data is collected, but not when only Trait data is collected.

When not to use treatment: predictor variables that are not based on distinct managements, or that are distinguished by information already contained in the trait (e.g. site, cultivar, date fields) should not be given distinct treatments. For example, a study that compares two different species, cultivars or genotypes can be assigned the same control treatment; these categories will be distinguished by the species or cultivar field. Another example is when the observation is made at two sites: the site field will include this information.

  • A treatment name is used as a categorical (rather than continuous)

    variable: it should be easy to find the treatment in the paper based on

    the name in the database. The treatment name does not have to indicate

    the level of treatment used in a particular treatment - this information

    will be included in the management table.

  • It is essential that a control group is identified with each study. If there is no experimental manipulation, then there is only one treatment. In this case, the treatment should be named 'observational' and listed as control. To determine the control when it is not explicitly stated, first determine if one of the treatments is most like a background condition or how a system would be in its non-experimental state. In the case of crops, this could be how a farmer would be most likely to treat a crop.

    Name: indicates type of treatment; it should be easy for anyone with the original paper to be able to identify the treatment from its name. Control: make sure to indicate if the treatment is the study 'control' by selecting true or false Definition: indicates the specifics of the treatment. It is useful for identification purposes to use a quantified description of the treatment even though this information can only be used for analysis when entered as a management.