Case Study - Philippines Metagora Pilot Project

CHAPTER 3: DEVELOPMENT OF THE SURVEY PLAN (SURVEY DESIGN) (page 3)

3.5.2 Sampling frame and sample size

The sampling frame adopted for the pilot survey was the listing of households by barangay used in the 2000 Census of Population and Housing (CPH). However, the main limitation of using the 2000 Census, aside from the fact that the numbers are not current, is that the identity of the household heads’ tribe is based on ethnicity and not on the individual’s self-ascription. The original plan to use the list of indigenous persons based on actual occupants of ancestral domains issued with Certificate of Ancestral Domain Titles (CADTs) was not pursued as the list was not available. The total sample size of 750 households for the pilot survey was pre-determined according to the following breakdown:

• Kankanaey Tribe - 250 households

• Bago Tribe - 150 households

• Bugkalot/Ilongot Tribe - 350 households

3.5.3 Sample Selection

The households in a barangay were grouped into clusters of five. Systematic sampling was used in the selection of the clusters. All the households in the sample clusters were enumerated. In determining the sample size for each barangay, proportional allocation was used following the pre-determined sample size for each tribe.

In the case of the Bugkalot/Ilongot ancestral domain, which encompasses five municipalities and a number of barangays, the sample allocation was modified. Unlike the rest of the barangays which, in their entirety, are part of the ancestral domain, only portions of the barangays in the municipalities of Kasibu, Dipaculao and Maria Aurora are part of the ancestral domain. Thus, the barangays in these three municipalities with less than 10 Bugkalot households were excluded from the survey.

Due to the extreme distances and difficult terrain involved in reaching respondents, it was not feasible to revisit sampled households that were not available. Additionally, the time constraints of the survey did not allow the random selection of a replacement household within the same cluster. Therefore, for all the tribes, a 100 percent replacement list of households taken from the next cluster of households ensured replacements for sample households no longer in the area, or which refused to be interviewed. Replacement was done for the following:

• If the sample household refused;

• If the sample household was temporarily away, on vacation, not at home;

• If there were no Kankanaey, Bago, or Bugkalot in the sample household;

• If the sample household no longer contained the anticipated occupants; and

• If the housing unit was vacant, demolished or destroyed.

3.5.4 Target Respondents

The household head or any responsible member of the household was interviewed using the structured questionnaire.

3.6 PREPARATION OF INTERVIEWERS' MANUAL

The Interviewers’ Manual was prepared by the NSCB Project Staff after the draft questionnaire was revised based on the results of the Technical Workshop in September 2005. With each further revision of the questionnaire, the Manual was revised accordingly. The Manual was patterned after the manuals usually prepared by the NSO for its regular survey operations.

A successful survey depends not only on how the questions are formulated but also on how these questions are asked. An interviewers’ manual, which provides instructions on how to ask questions, how to handle problems that may arise during the interview, and how to correctly record answers to the questions, is thus an important tool in achieving the goals and objectives of a survey.

The manual serves as useful reference for the interviewer, which he/she can consult if problems arise during fieldwork. The manual should therefore be as comprehensive as possible.

In preparing the Interviewers’ Manual, consideration was given to the definition of concepts and terms that were used in the survey questionnaire and explanations on why a particular question is being asked. Other important features of the manual are:

1. objectives of the pilot survey;

2. survey design;

3. survey organisation and operations;

4. duties of the interviewer, and

5. general instructions on how to properly ask questions and record answers.

3.7 NSCB SURVEY REVIEW AND CLEARANCE

The final survey questionnaire, including the sampling design and Interviewers’ Manual, was approved and given clearance with Approval Number CHR-0504-01 expiring on 31 December 2005 through the Statistical Survey Review and Clearance System of the NSCB. The System is a coordinating mechanism instituted by the NSCB to ensure conformity of surveys conducted by the government with standard definitions, concepts and classifications, thus enhancing the comparability and accuracy of statistics generated.

For further information, please refer to Appendix 3.1, Appendix 3.2, Appendix 3.3a, Appendix 3.3b, and Appendix 3.4 of this Case Study.