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Default Variable Values

In order to avoid ambiguity, a number of special codes are used consistently throughout each database. Although the specific meaning may vary slightly from variable to variable, the sense or type of context is consistent.

One of the most persistent ambiguities associated with extensive data collection by multiple participants occurs when a data field is left blank: did the person in the field forget to fill in that datum, or was the datum not relevant in the particular context? To avoid this sort of problem, it is very important that all fields have some value. Until a stand-alone data entry application can be developed, we strongly recommend that spreadsheet tables be 'filled' with a placeholder value (e.g. -99), which is then replaced by data from/in the field.

Golondrinas databases will include the following special values:

-99 Often used as a place-holder to indicate that these data have not been coded. This will be seen most commonly in the context of data-entry forms written for a stand-alone application. Participants using spreadsheets or equivalent data forms provided by us are strongly advised to copy the model layout observation before entering data for a specific case.
-9 Data unknown. No more specific value can be given.
-8 Not applicable, usually because the code for some other variable makes coding this variable nonsensical. For example, in a nest where all eggs were depredated, the variable 'hatchdate' would get a code of -8.
-7 Partial knowledge, but not sufficiently accurate for the preferred code. Usually relevant for numeric variables only. For example, if a nest is known to have produced some fledglings, but the actual number is not known.

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