Using Area Frame for Agricultural Censuses and Surveys

Using Area Frame for Agricultural Censuses and Surveys: The Philippines Experience by: Rosalinda M. Garcia, Bureau of Agricultural Statistics Minerva Eloisa P. Esquivias, National Statistics Office Regional Workshop on Sampling for Agricultural Censuses and Surveys May 14– 18, 2012 Bangkok, Thailand

2 Outline 1. Introduction 2. The BAEcon Area Sampling Frame Study 3. The Area Frame Study for the Census 4. Concluding Notes National Statistics Office www. census. gov. ph

3 Introduction Ø Area Frame – sampling frame where segments of land are sampling units Ø List Frame – listing of holdings or Holders Ø Multiple Frame – combination of Area Frame and List Frame National Statistics Office www. census. gov. ph

4 Introduction Ø Area Frame § Its stability is its strength, thus non-sampling errors are reduced. § Data collection is based on land units that are fixed. § Not integrated in the Philippine Agricultural Statistical System. § Two Experiments/studies were undertaken 1. The BAEcon Area Sampling Frame Study 2. The Area Frame Study for the Census National Statistics Office www. census. gov. ph

5 The BAEcon Area Sampling Frame Study § Done by the Bureau of Agricultural Economics (BAEcon), now known as the Bureau of Agricultural Statistics (BAS) § Done in 1980 under a Project between Government of the Philippines and USAID § Conducted for only one province (Pangasinan) § Area Sampling Frame (ASF) estimates were compared with Rice and Corn Survey (RCS) estimates National Statistics Office www. census. gov. ph

6 The BAEcon Area Sampling Frame Study Area Sampling Frame for Pangasinan: § Made use of Landsat imagery, aerial photography and topographic maps § Conducted a pilot survey o using random sample of 72 segments, approx. 25 ha. in size o Observed standing crops; measured crop area; interviewed farmers to determine crop production for past six months National Statistics Office www. census. gov. ph

7 The BAEcon Area Sampling Frame Study Area Sampling Frame for Pangasinan: § Compared estimates obtained from area frame survey and BAEcon’s Rice and Corn Survey where samples were obtained from a List Frame § Results o ASF estimate of harvested area for rice was 28% higher than RCS estimate for July-December 1979 ref. period o ASF estimate of rice production was 18% higher than RCS estimate o ASF estimates for corn area harvested and production were a lot lower than the RCS estimates National Statistics Office www. census. gov. ph

8 The BAEcon Area Sampling Frame Study Area Sampling Frame for Pangasinan: § § § Involved a small experiment which yielded inconclusive results Needs more current aerial photography and use of multitemporal Landsat Imagery Cost was formidable National Statistics Office www. census. gov. ph

9 The Area Frame Study for the Census § Done by the National Statistics Office, the Bureau of Agricultural Statistics, and the Statistical Research and Training Center. § Done in 2006 under a Project between the three statistical offices for the 2012 Census of Agriculture and Fisheries (CAF). § Conducted in the municipality of Quirino in Isabela province. National Statistics Office www. census. gov. ph

10 The Area Frame Study for the Census Area Frame Experiment in Quirino, Isabela: § Made use of Landsat imagery, Google Earth imagery, NAMRIA topographic maps and NSO provincial/ municipality/barangay shape files. § Conducted ground truthing o Adopted the LUCAS procedure using point sampling frame. o PSUs and SSUs were located using GPS and magnetic compass. o Recording the characteristics of sample points on survey questionnaire. National Statistics Office www. census. gov. ph

11 The Area Frame Study for the Census § Results revealed that technology was viable to complement the list frame. o Cost of acquiring high-resolution satellite spatial imagery is decreasing. o Land. Sat imagery can be used in stratifying land cover/land use strata. o Google Earth images can be used as alternative to the costly ground truthing activity. § Assessment (Steering Committee) o No immediate relevance o Required satellite maps as a tool are unavailable for all provinces National Statistics Office www. census. gov. ph

12 Concluding Notes Limitations of Using Area Frame for Philippine agricultural surveys § § § Cost Heterogeneity nature of agriculture in the country. Farm parcels are becoming smaller. Mixed cropping on the same parcel is applied to maximize use of area. Not all farmers follow same cropping cycle in locality, thus several activities may happen in adjacent parcels. National Statistics Office www. census. gov. ph

13 Concluding Notes § § More in-depth studies could be made to look into the various agricultural practices in the country. Area Frame experts, program implementers need to consider situation of farmers in particular and agriculture situation in general to serve as inputs in the planning for and in using area frame. Capability building for staff Procurement of high resolution images National Statistics Office www. census. gov. ph

Thank You! URL: www. bas. gov. ph Email: info@bas. gov. ph URL: www. census. gov. ph Email: info@census. gov. ph