Any picture of performance painted by a set of performance indicators will always be an abstraction of real performance, and as such will always be subject to the vagaries of incomplete assessment, sampling error and injudicious interpretation.
The details on time of assessments, sample size and analyses used in the two stages are depicted in Table 1.
Error assessment: sampling, spatial autocorrelation, error matrix, locational accuracy, discrete multivariate statistical techniques and reporting standards.
The risk assessment was carried out by a member of the OER staff (trained at the 1st EWGLI training course "Investigating outbreaks of legionnaires' disease: risk assessment, sampling and control", November 2004, Health Protection Agency, London).
This study presents a simulation-based assessment of sampling strategies employing ALS with focus on large-area (27,400 km2) biomass estimation.
Few studies tried, for instance, to give a population-based assessment by sampling according to a population norm.
Nevertheless, the correlation structure of large-scale assessment samples calls for such techniques.
To allow accuracy assessment samples were also analyzed using the AOAC reference method.
For the system-wide assessment, sample locations were based on a probabilistic survey design.
Critical issues in children's environmental research discussed in this paper include specific needs of study design, exposure assessment, sample collection and ethics.
