Section 1 Survey Sampling

These pages document data sources and methods used to generate detailed spatially-referenced characteristics of farm households interviewed as part of AgResults 2015-2017 program evaluation in Nigeria, Kenya, and Uganda.

All statistics are derived using the geospatial locations of surveyed respondents. However these locations are sometimes missing or invalid. In the case of missing coordinates we generate spatial statistics at the centroid of the matching administrative unit (the lowest level unit that may be mapped with any confidence, i.e. LGA for Nigeria, county for Kenya, and district for Uganda). Note that another approach would be to derive average statistics over the entire administrative unit, however this approach is more resource-intensive.

1.1 Nigeria

2,065 households are sampled in Nigeria. There are 81 households missing coordinates and 414 possibly invalid locations.

Tab. 1.1: Survey Sampling across LGAs and missing Household Locations
    Nigeria Household GPS Locations
State LGA Obs. Missing Invalid
Kaduna Birnin-Gwari   133     3    10
  Chukun     3     1     2
  Giwa   151    26    17
  Igabi     7     0     0
  Ikara    84     3    11
  Jema’a    54     9    18
  Kaura    12     7     0
  Kauru    22     0     5
  Kubau   160     0    23
  Kudan    49     4    18
  Lere    62     1     0
  Makarfi   109     3    28
  Rogo    20     0     1
  Sabon Gari    29     0    20
  Soba   157     0     0
  Zaria    21     4    17
  All 1,073    61   170
Kano Bebeji    34     1     3
  Bunkure    19     0     0
  Dawakin Kudu    14     1     8
  Doguwa    35     0     0
  Gwarzo    40     1     3
  Karaye    39     2     0
  Kibiya     9     0     0
  Kiru    14     1     0
  Kura    10     0     0
  Rano    10     0     0
  Rimin Gado    16     0    13
  Rogo    31     0     0
  Tofa     5     0     0
  Tudun Wada    83     8     0
  All   359    14    27
Katsina Bakori   256     2    93
  Danja    90     0    18
  Funtua    83     1    24
  Kahur    71     2    37
  Malumfashi   113     1    35
  Sabuwa    20     0    10
  All   633     6   217
All 2,065    81   414

There are 414 households with GPS coordinates that do not fall within their recorded LGA. In the majority of instances the distance is negligeable (under 10km) and this might not affect any of the spatial estimates. In a few instances the errors are troublesome (over 40km). For documentation purposes households with problematic locations are highlighted on the map below.

Households with Invalid GPS Locations, Nigeria

Fig. 1.1: Households with Invalid GPS Locations, Nigeria

1.2 Kenya

In Kenya data was collected over 2 rounds with some attrition, and household locations do not necessarily match across rounds. We use a general approach to impute missing, invalid, and/or conflicting coordinates:

  1. if both GPS locations seem valid (i.e. they are located in the reported county), we use their middle point (coded mean in table below)
  2. if only 1 of the 2 locations is valid, we use that one (coded bl1 or bl2)
  3. if no location is valid (both fall outside of a recorded administrative unit), we use that administrative unit centroid (coded centroid).

5,235 households are sampled in Kenya. There is a total of 88 households with missing or invalid coordinates. Table below shows a breakown of imputed household locations across Kenya’s 8 regions and 47 counties. Note that we could not locate a map of Kenya’s sub-counties.

Tab. 1.2: Survey Sampling across Counties and missing Household Locations
    Kenya Household GPS Locations
    Status  
Region County centroid bl2 bl1 mean All
Central Kirinyaga     3         1     4
  Murang’a     1           1
  All     4     0     0     1     5
Coast Kilifi     1           1
  Taita Taveta     1           1
  All     2     0     0     0     2
Eastern Embu     124   259   582   965
  Kitui    11   151   247   583   992
  Machakos    13    17   111   737   878
  Makueni     4    78   192   601   875
  Meru    13    69   208   624   914
  Tharaka     7           7
  All    48   439 1,017 3,127 4,631
Nairobi Nairobi     1           1
  All     1     0     0     0     1
Rift Valley Baringo       7     7    53    67
  Bomet    14    12    15    45    86
  Kajiado     1           1
  Kericho        11    31    42
  Laikipia        12    49    61
  Nakuru     7       5    55    67
  Nandi     5     1     9    50    65
  Narok     6    21    41    22    90
  Trans Nzoia       1     8    51    60
  Uasin Gishu       1     5    51    57
  All    33    43   113   407   596
All    88   482 1,130 3,535 5,235
Households Locations across Counties, Kenya

Fig. 1.2: Households Locations across Counties, Kenya

1.3 Uganda

1,479 households are sampled in Uganda. There are 55 households missing coordinates. Missing coordinates are imputed using village centroids (these imputed locations are shown on the map below in red).

Tab. 1.3: Survey Sampling across Districts and missing Household Locations
    Uganda Household GPS Locations
District County Obs. Missing
Amuria Amuria County     9     0
  Kapelebyong County    20     0
  All    29     0
Amuru Kilak County   142     3
  All   142     3
Apac Kwania County    19     0
  All    19     0
Arua Ayivu County    20     4
  Madi-Okollo County    10     3
  Terego County    10     3
  All    40    10
Bushenyi Bushenyi-Ishaka Municipality     9     0
  Igara County East    10     0
  Igara County West    30     0
  All    49     0
Gulu Aswa County    29     0
  Omoro County    29     0
  All    58     0
Isingiro Bukanga County     8     2
  Isingirocounty North    29     6
  All    37     8
Kabale Ndorwa County East    20     4
  Ndorwa County West    20     4
  Rubanda County East    21     4
  Rubanda County West     9     2
  All    70    14
Kabarole Bunyangabu County    19     0
  Burahya County     9     0
  Fortportal Municipality    21     0
  All    49     0
Kamuli Bugabula County South    10     0
  All    10     0
Kanungu Kinkinzi County West    10     2
  All    10     2
Kasese Bukonjo County West    10     0
  Busongora Countynorth    19     0
  Kasese Municipality     9     0
  All    38     0
Kibaale Buyagaeast County    40     0
  Buyagawest County    20     0
  Buyanja County    19     0
  All    79     0
Kiruhura Kazo County    10     0
  Nyabushozi County    20     0
  All    30     0
Kyenjojo Mwenge County North    23     0
  Mwenge County South    26     3
  All    49     3
Luweero Katikamu County North    10     0
  All    10     0
Masaka Bukoto County Central    47     0
  Bukoto County East    13     0
  Masaka Municipality    21     0
  All    81     0
Masindi Bujenje County    19     0
  Buruli County    16     0
  All    35     0
Mbale Bungokho County North    20     0
  Bungokho County South    40     0
  All    60     0
Mityana Mityana County South    10     0
  All    10     0
Mubende Buwekula County    30     0
  Kasambya County    65     0
  Kassanda County North    40     0
  Kassanda County South    44     0
  All   179     0
Mukono Mukono County South    10     0
  All    10     0
Namutumba Busiki County    10     0
  All    10     0
Ntungamo Kajara County    72     0
  Ruhaama County    67     0
  Rushenyi County    27     0
  All   166     0
Oyam Oyam County North    84     6
  Oyam County South    73     4
  All   157    10
Pader Aruu County    10     0
  All    10     0
Wakiso Kyadondo County North    21     0
  All    21     0
Yumbe Aringa County    21     5
  All    21     5
All 1,479    55
Households Locations across Districts, Uganda

Fig. 1.3: Households Locations across Districts, Uganda