NASS OMB Docket Review

April 5, 2018

National Woodland Owner Survey

NASS OMB Docket Review

Peter Quan: Mathematical Statistician

Sampling and Frame Development Section, Section Head

BACKGROUND

The United States Department of Agriculture Forest Service (FS) is responsible for the inventory and assessment of forest and related renewable resources. The National Woodland Owner Survey (NWOS) – designed to collect information on the nation’s forestland – has been conducted 11 times since 1976. The FS is renewing their previously approved NWOS for another three year cycle.

SAMPLING FRAME and SAMPLE

The NWOS Sampling Frame comprises all forested land in the US. The sampling frame is divided into hexagons before selecting one point within each hexagon. Thus, the size of hexagons in a given area is a function of the number of samples allocated to that area. The sample size was determined to achieve a coefficient of variation of at most 15%.

REMARKS and SUGGESTIONS

The sampling frame, sample size determination and sample selection and estimation procedures are all fine. However, it is interesting FS is using the same sample size for all states. An idea would be to allocate the appropriate number of samples to each state to achieve corresponding target CVs. The target CVs can be lower for areas that have relatively less forest land areas and higher for areas that have relatively more forest land.

The process to maximize response rates and to deal with non-response is very similar to NASS’s procedures: cognitive testing, pre-notice, initial questionnaire, reminder, second questionnaire, telephone interview and electronic version option.