Factors in 3-column text format files

Associated with each record are often one or more factors which define the conditions under which that sample was taken (sites, times etc). These could be copied and pasted from a sample table held in the relational database to a factors sheet set up for that data in PRIMER – see section 2 for how to set up factors within PRIMER – but this categorical information on the data structure is typically output from the relational database as part of each record. If there is no access to the original data¬base table of factors, such a record format can be used by PRIMER 7 to populate its factor table. This is why the above 3-column example does not contain just three columns, in this case! There is a fourth blank column (i.e. an extra tab) and then two (alphanumeric) factor level columns – though there could be many more – which here define the block and disturbance status for each record. Of course each combination of the two factor levels is repeated as many times as there are numbers of species observed in that sample, and if these entries are not identical an error message will result. Then (if needed) follows another blank column (extra tab) and any ‘factor levels’ defined on the variables (termed indicators, see Section 2); here this indicates which species have been identified.