Uncertain

Uncertain is used to record that the key author is uncertain or does not know whether a given state occurs or does not occur in a given entity.

Uncertain will sometimes be applied to all states of a feature and sometimes only to one or a few states of a feature. For example, consider a key to plants which includes a feature referring to the colour of the fruit. It may be that one species in the key is known only from a few specimens and fruits have never been observed. In that case, all the states of the Fruit colour feature would be scored Uncertain. Another species may be poorly known and yet it is clear that the fruits are not white or coloured, but they could be black or dark grey. In that case, white and the coloured states could be scored Absent and dark grey and black both scored Uncertain.

In the Lucid3 Player in normal identification mode, Uncertain is treated the same as Common. That is, if an entity e is scored Uncertain for state e will remain in Entities Remaining when a user chooses s. This is appropriate behaviour for an identification, as e should not be falsely discarded if a key user has more information about it than was available to the key builder.

The behaviour of the Player can also be changed by un-checking the Retain Uncertains menu option, in which case Uncertain is treated the same as Absent. This would be appropriate if a user of the key is querying the Player to return a list of all entities known to have state s (rather than all entities that may have s).

For numeric features, Uncertain is coded as a special value in the Numeric Coding dialog box. See the topic Scoring numeric features for more details.