Socio economy: Mile 46

Modelling of decision making and bio-economic dynamics in communal lands


Photographs from left to right : Man threshing millet - Woman winnowing harvested millet - Woman pounding millet seeds to flour
Ox-drawn sledges are used for transportation purposes - Man made bush fires are one of the main biodiversity threats (E-Mail to Judith Hecht - owner of the photographs)

Decision making

The object of this WP 2 is to construct a dynamic bio-economic model of a communal village. The objective function of the model is maximizing utility subject to several constraints. The utility function has been identified with a modified conjoint analysis (CA) approach. CA is a method that raises values for the overall utility on the basis of preference judgments of decision makers in a given choice setting. In general this method is used in market research.

Method I

For the experimental design of CA different stimuli (bundles of concrete levels of considered factors) are presented to respondents which consist of desirable and non-desirable levels of the considered factors. This imposes respondents to weight the importance of the different factors relative to one another.

The five relevant factors for this case study and their corresponding levels were identified during interviews with key-informants (Table 1).

 Table 1:Considered factors and their corresponding levels - Source: Judith Hecht

An orthogonal design was produced by SPSS with 20 profile cards (one profile card can be seen in Figure 1).

Figure 1:Profile card - Source: Judith Hecht

top left corner: factor symbol of family, cultural and social activities - factor level: 8 days
top right corner: factor symbol of off-farm labour activities - factor level: 300N$ per month
bottom left corner: factor symbol of crop production activities - factor level: insufficient
bottom right corner: factor symbol of animal production activities - factor level: 20 cattle and 11 goats
central: factor symbol of other activities using natural resources - factor level: sufficient

Information sheets for the five factors were designed, which explained the different factor components, factor symbols and factor levels
(Figure 2).

Figure 2:Information sheet for crop production activities - Source: Judith Hecht

Method II

For CA interviews respondents were asked to consider each profile card as a possible future life situation. The following interview procedure was used:

  • Explanation of the approach with information sheets and two example cards
  • Rough sorting of profile cards in three piles 'prefer','reject' and 'neither prefer nor reject' (Picture left)
  • Final ranking of the different piles regarding the preferences of respondents. This was facilitated by a magnetic board on which all cards of the different piles were visualised (Picture right)
  • Summarising the different part orders in one global order

Left picture: Rough sorting - Right picture: Final ranking - Source: Judith Hecht


Results of CA quantitatively prove a high preference for animal husbandry (37.5%) followed by off-farm labour (28.5%) and crop production (19.2%) (Figure 3).

In contrast the decomposition in men and women respondents demonstrates, that women (22.8%) seem to assign crop production activities a higher utility level than men (16.2%) (Figure 4a/4b). This might be an indicator that women are more anxious to assure an adequate nutrition of the family.

Figure 3:Relative importance (%) of household activities
Source: Judith Hecht (calculation n=66)

Figure 4a:Relative importance (%) of household activities for men
Source: Judith Hecht (calculation n=36)

Figure 4a:Relative importance (%) of household activities for women
Source: Judith Hecht (calculation n=30)


The acquisition of assets and cash income represents the main objective of communal farmers. However, the increase of livestock and field numbers will contribute to further degradation of rangelands and forests. This might cause a supplementary instability of the eco-system and thus the nutrition base.


S11 Socio-economy WP 2: Modelling of decision making and bio-economic dynamics in communal lands:

  • Farming system research (mid of June till mid of August 2005)
  • Conjoint-Analyse (mid of August till end of September 2005)