All observations are validated before they are entered in the NDFF to ensure they meet strict quality requirements of NDFF. In order to generate occurrence maps, formulate policy advice, plan developments, carry out academic research and utilize the NDFF in other ways, it is important that its data is comparable. This means that all data must be validated and entered in the same way. This prevents mistakes and ensures that occurrence records can be interpreted correctly.
Firstly, observations are checked on species, number, data, and location in the Netherlands. Secondly, content validation is carried out based on knowledge rules. This includes a number of standards, such as time of year and place of observation. For example: an observation of a butterfly in December when this species can only be observed in August is extremely unlikely. Such an observation therefore needs further research. This happens in the manual validation phase.
Observations that do not meet the standards are manually checked by a validation team. This team handles about 10% of all observations. When there are doubts about an observation, the validation expert contacts the observer. They decide together whether the observation is valid.
Validation has nothing to do with tracking down mistakes. When an observation is rejected, that merely means there is insufficient certainty or evidence to justify the inclusion of the observation. Such observations are not accessible to NDFF users, but will remain accessible to the observers who made them.