Namibia - Indigenous Natural Products

Members of PPOs and their households
Household Survey

The sample design was comprised of households selected from lists of PPO producers. The sample design was originally going to be a two-stage design in which the first-stage sample units were communities on the PPO list (e.g., villages) and the second-stage sample units were households within the selected communities. Unfortunately, it was not possible to obtain community locations for many of the producers in the INP sample frame, so it was not practical to implement the original concept of selecting a two-stage sample for the INP survey. In fact, few variables were available in the PPO frame that could be used to construct an analytical survey design. Apart from PPO, the only variable useful for constructing an analytical design was INP species. Therefore, it was decided to select a stratified single-stage sample from the frame, where stratification would be by INP species. The baseline sample frame included membership from the 28 PPOs that could provide membership lists out of 63 targeted PPOs.

Focus Group Discussions

A total of 40 FGDs were conducted with members of PPOs during midline and endline data collection. For the midline data collection, 12 PPOs were selected to cover a wide range of PPO characteristics such as geographic location, implementer, and institution type. For each PPO, two focus groups were conducted: one with the members of the management staff and one with members who did not hold a management position with the PPO, bringing the total of midline INP FGDs to 24. For the endline data collection, 8 of the original 12 PPOs were re-selected and similar to midline, FGDs were conducted with management and non-management members, bringing the total of endline INP FGDs to 16.

Recruiting Focus Group Discussion participants was mostly done with the help of the senior staff of the conservancies and the PPOs, typically either chairpersons or coordinators whose contact information was received from the relevant implementer. The teams made phone contact prior to arriving at conservancies or PPO areas and made arrangements to meet upon arrival. All recruitment criteria and procedures were discussed in these first meetings. PPO representatives then listed the names and locations of the appropriate respondents. Where possible, with the help of the chairpersons or coordinators, the field team made phone calls to the identified respondents to make arrangements to meet and discuss the study and invite them to participate. In other cases, where time allowed, the chairperson or coordinator organised a meeting for the team to meet with and conduct all necessary arrangements with a pool of potential respondents at a central location. From this pool, respondents were then selected as per the recruitment protocols.

Key Informant Interviews

Sample development for the key informant interviews (KIIs) was a joint effort between the NORC, MCA-N, and Survey Warehouse teams. NORC produced a list of different types of respondents to potentially interview, and the INP expert on the evaluation team refined the list and suggested names of individuals in some categories. After this list was shared with MCA-N, NORC met with MCA-N staff to discuss the list, further refine it, and obtain contact details for potential respondents. The list of potential KII respondents continued to evolve throughout the recruitment process.


A total of 19 INP KIIs were conducted, 12 during the midline round and 7 during the endline round.


Household Survey

While the target sample size for the INP household survey was 500 households, the final baseline dataset only includes 296 household interviews. As a result, in addition to the 296 households from the baseline survey, the endline INP household survey also includes an additional 204 INP households in order to reach the original target of 500 households and to provide additional data points for the endline analysis. These additional households were sampled from the original baseline sample frame in order to maximize comparability. It is important to note the following points concerning this additional sample:

(1) Of the 28 PPOs represented in the baseline sampling frame, 18 PPOs are represented in the final baseline dataset. Because NORC does not have baseline information for the PPOs which were not surveyed at baseline, including them at endline would not be useful for the CS/INP evaluation given that a pre-post analysis would not be possible. Therefore, the additional 204 endline households were drawn from the 18 PPOs represented at baseline only.

(2) However, the 18 PPOs represented in the baseline dataset do not cover Commiphora. Given that Commiphora is one of the main INPs targeted by the intervention, the final endline sample also included Commiphora PPOs (in addition to the 18 PPOs included at baseline). While a pre-post analysis would not be possible for these harvesters, the data from these harvesters can be used to generate descriptive statistics about the endline period.


NORC was asked to complete 500 total INP surveys. However, given the problems with the initial frame, it was impossible to reach this target. At baseline, 631 attempted interviews were attempted but 502 were considered "within scope." The overall response rate based on the households within scope is: 296/502 = 59%.

For the endline survey sample there were two different “pools” of people: a pool of 296 respondents who were interviewed at baseline, and a pool of 204 new respondents interviewed at endline, for a total target of 500 respondents. Where INP households could not be located, supervisors used the sample replacement list provided by NORC to locate the next replacement. Overall, 496 interviews were completed against a target of 500, for a response rate of 99%. A total of 143 replacements were made.


Harvester Sampling Weights for Baseline and Endline by INP:

The baseline sample is constructed from 18 PPOs out of approximately 63 that were operational in 2009. The number of households selected was established by MCA prior to NORC being contracted to conduct the survey or evaluation. Harvesters were randomly selected from a sampling frame comprising PPO member lists of the subset of PPOs specializing in the respective INP. With this in mind each weight is calculated as the reciprocal of the probability of selec­tion. This requires dividing the population size by the actual baseline or endline sample size. The use of these weights depends on whether one is conducting panel analysis or cross-sectional comparisons. For panel analysis the baseline weights are applied to both rounds. For comparison of discrete cross-sections, the baseline and endline weights in the table are applied accordingly. The reason for this difference is that the latter includes additional observations randomly sampled from the same population so the larger sample implies that each observation is weighted less.

Baseline weights by INP:
- Devil's Claw: 14.226
- Marula: 10.621
- Ximenia: 5.814

Endline weights by INP:
- Commiphora: 5.825
- Devil's Claw: 5.765
- Marula: 10.191
- Mopane: 5.333
- Ximenia: 5.732