It is appropriate, in any rodent management programme, that those who undertake the control have an expectation of the time-scale over which control is to be achieved. As far as the anticoagulants are concerned, an appropriate initial time scale for field control might be set at 14 – 35 days. If control is achieved within this time then targets and expectations have been met.

If however the records indicate that rodent activity is still present after this period, then it is appropriate for a review to be undertaken to determine possible reasons for the prolonged treatment. This review should include not only those undertaking the rodent control operations and running the programme, but also those who manage and are responsible for the site at which the control is being undertaken.

This review should seek, using the records available, to identify why the control is prolonged and what action is necessary to achieve success. All aspects of the operation should be reviewed by a close analysis of the data. These should include the suitability of the initial survey, the correct bait presentation, the palatability of the bait, the baiting density and visit frequency, the degree to which environmental management might be improved to assist with control and any other aspects relating to the nature of individual infestations.

Amongst the issues reviewed must be the bait take profile for the treatment. If the records indicate that bait consumption is poor the baiting strategy should be reviewed. If the bait consumption is good, but control is not being achieved, then the possibility that the target rodents may be resistant should be considered. The outcome of the review should clarify the causes of prolonged treatment times. To search for reasons of control failure also see the checklist.

A further purpose of any regular review of progress when using rodenticides must be to ensure that label requirements are being observed. The rodenticide label identifies exactly how the rodenticide manufacturer and the registration authorities intend and expect the rodenticide to be used to achieve maximum efficacy and to ensure safe use. In many countries the label is not only a set of instructions designed to maximize efficacy, but is also a legal document which identifies the legal requirement when using the rodenticide.