Statistical Sampling For Reinspections
Beginning in 2006, ATFS will begin selecting properties for reinspection using stratified random sampling.
In 2002, ATFS contracted with Virginia Tech’s College of Forestry to explore the concept of stratified random sampling as a means of reducing the number of annual reinspections necessary for program policy conformance.Selecting properties to be reinspected through stratified random sampling allows for a significant reduction in total number of inspections necessary while providing a statistically valid answer in the form of the total percent of ATFS certified acres in conformance with AFF’s Standards of Sustainability for Forest Certification.
By nationally stratifying properties into acreage categories,required reinspections drop from approximately 8,000 in 2006 to 1180. The results would be 95% accurate with a margin of error of ± 2 percent. Thus, upon completion of annual reinspections, ATFS will annually report that X percent of ATFS certified acres are in conformance with AFF’s Standards of Sustainability. The obvious advantage from sampling is the greatly reduced burden on state programs to perform reinspections.
State programs are given the option of completely adopting the sampling system, or continuing with business as usual.The difference for those continuing with business as usual is that those properties selected in the sample are required to be inspected by year’s end. Those state programs that adopt sampling entirely will only be responsible for inspecting those properties selected in the sample. States should witness a 75% or greater reduction in their reinspections. Look for further communications from your state committee regarding the reinspection method they have chosen.
