Use of individualCount or organismQuantity

[CherineJ]

Both terms, individualCount and organismQuantity, can be used to describe the quantity of organisms. According to OBIS individualCount is the older term and less flexible than organismQuantity. The Darwin Core developers acknowledge that the terms are somewhat redundant and there have been discussions going on whether individualCount should be deprecated, as the same information can easily be stored in organismQuantity. It is however argued that individualCount is a standard term that is widely used in certain disciplines, in which both terms are also seen as non-redundant because they can have different meanings (especially in paleontology) and should therefore stay active. There is also a call that there first should be a standardized vocabulary established for organismQuantityType before deprecating individualCount.

organismQuantity

• always has to have a corresponding dwc:organismQuantityType
• is a number or enumeration value for the quantity of dwc:Organisms
• is not only describing number of individuals but can also describe, for example, % biomass or a category on a scale

individualCount

• the number of individuals present at the time of the dwc:Occurrence
• has no unit, as it is count data (see also #7)

Generally, it seems that for our biological data organismQuantity might be the better term to use, as it is more flexible and might be more persistent in the long run. For individual counts it looks like both terms can be used interchangeably.

Both terms are part of the occurrence table according to Darwin Core, however OBIS recommends to "use (extended) measurement or fact for quantitative measurements because of the standardization of terms and the fact that you can link these measurements to sampling events and factual sampling information".

[CherineJ]

Conclusion

We use organismQuantity where possible, as it can easily hold the same information as individualCount but is also more flexible to store other quantitative information. Based on the discussions, it might also be more persistent in the long run.