Sampling Method

How are the survey respondents being selected?

During the 1996-1997 Rice-Based Farm Household Survey (RBFHS) round, the top 30 rice-producing provinces were selected as target provinces. These are based on their ranking of their averages of rice harvest area from 1992 to 1996.

The target provinces were then divided into four groups (strata):

Table 1. Sample provinces for the 1996-1997 Rice-Based Farm Household Survey (RBFHS)
Group 1 Group 2 Group 3 Group 4
Pangasinan Iloilo Tarlac Sultan Kudarat
Nueva Ecija Isabela North Cotabato Occidental Mindoro
Camarines Sur Maguindanao Quezon
Cagayan Leyte Albay
Zamboanga del Sur South Cotabato
Bulacan Pampanga
Oriental Mindoro Davao del Norte
Bohol Ilocos Norte
Bukidnon Northern Samar
Agusan del Sur
Laguna
Zamboanga del Norte
Davao del Sur
Agusan del Norte
Aurora

Each group must form the 25% of total harvest area of all target provinces. In agreement, equal sample size across provinces in each group were set at 155, 120, 90, 60, respectively.

Table 2. Sample sizes per target province throughout RBFH survey rounds
Province1996-19972001-20022006-20072011-20122016-2017
Agusan del Norte6060256060
Agusan del Sur6060416060
Albay6060496060
Antique1----60
Apayao2----60
Aurora6060576060
Bohol9090758686
Bukidnon9099488686
Bulacan9082778686
Cagayan120120114116116
Camarines Sur12011490116116
Capiz1----60
Compostela Valley3-26122660
Davao del Norte6034193460
Davao del Sur6060326060
Davao Oriental4-60606060
Ilocos Norte6052576060
Iloilo12012088116116
Isabela12012689116116
Kalinga2----60
Laguna6072566060
Lanao del Sur1----60
Leyte9099798686
Maguindanao9090468686
Negros Occidental5----90
North Cotabato9090418686
Northern Samar6072506060
Nueva Ecija155155110151151
Nueva Vizcaya----60
Occidental Mindoro6060516060
Oriental Mindoro9099858686
Palawan1----60
Pampanga6050566060
Pangasinan155155147151151
Quezon6060526060
South Cotabato6060496060
Sultan Kudarat6060536060
Tarlac9090768686
Western Samar1----60
Zamboanga del Norte6060426060
Zamboanga del Sur9028226060
Zamboanga Sibugay-62512660
TOTAL2,5002,5851,9992,5003,164

NOTES:

All provinces highlighted in green were only added during the 2016-2017 RBFH survey round.

1 Antique, Capiz, Lanao del Sur, Nueva Vizcaya, Palawan and Western Samar are included as they will be potential source of increase in rice production.

2 Kalinga and Apayao are included to represent the Cordillera Administrative Region.

3 Compostella Valley was still part of Davao del Norte until it was made independent in 1998.

4 Davao Oriental was included because of its potential importance to hybrid rice commercialization.

5 Negros Occidental is included in preparation in the creation of the unified Negros region.

Barangays (villages) are classified into two (2) classes:

irrig.png

Irrigated

rainfed.png

Rainfed



An irrigated barangay must have more than 50% of their rice area irrigated, while the opposite was classified as rainfed.

Using simple random sampling, the target irrigated and rainfed barangays were drawn from list of barangays in the province. Equal number of barangays across provinces in each group were set at 17. 13, 10, and 7, respectively.

For 1996-1997 survey round, a household is chosen using the right coverage approach.

rightcoverage.jpg

An enumerator counts three houses to the right of a pre-selected landmark in the barangay (ex: barangay hall, school or church).

Then, the members of the household living in the third house were asked if they were farming rice.

If they say yes, the enumerator will begin interviewing the respondent. If not, the enumerator would continue to visit every third house to the right until he/she finds a rice-farming household.

In the succeeding RBFHS rounds, same respondents from the previous round were interviewed again.

Replacing only when farmer-respondent:

  • was deceased,

  • has migrated to another place, and

  • permanently stopped from rice farming.