Inter-Calibration Exercise - Planet WGSW-24010 User Manual

7.4 Inter -calibr ation exer cise
It is recommended that each surveyor should attend an inter-calibration exercise every year. This
is designed to assess the level of consistency between surveyors and has some similarities to a
Level 2 audit survey, but involves more surveyors and the surveys are always done
simultaneously on the same day. The inter-calibration may be between individual surveyors
within a team, or between survey-teams. Preferably, the exercise should be held once some
macrophyte surveys have been completed rather than at the beginning of the survey season,
although it can be combined with the annual refresher training. The difference between the
refresher training and the inter-calibration exercise is that the former includes instruction in the
method (even if only an overview of the key points), whereas the inter-calibration need only
involve a field comparison of surveys. If the two are combined, then the inter-calibration can
form the final part of the field training session.
All participants meet in the field, with one person having overall responsibility. A 100m survey
length is then selected and marked, and each surveyor individually surveys this length. The
exception to this is where surveyors consistently work together in teams, whereby the survey-
team is the surveyor-unit being assessed. In these cases, individual teams survey the site under
the direction of the usual 'principal surveyor'. Abundance of individual macrophyte species is
recorded using the 9-point Scale C. Although the drawing of a sketch map is optional for
assessment purposes, at least one sketch map should be drawn per exercise, with relocation
features for future reference. Results of the surveys should not be discussed until after all surveys
have been completed.
Data should be analysed afterwards to determine the level of consistency between surveyors. A
report should be produced on the data, identifying inconsistencies and recommending measures
to address them, eg any areas where further training is needed. As with the Level 2 QA protocol,
this inter-calibration allows for an on-going assessment of the errors involved in all aspects of the
surveying.
Where possible, different types of site should be surveyed in this manner. It should be
remembered that results from turbid and/or deep water sites will not be as accurate as those
where the bed is visible at all times.
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