6. reason why the measurement process should not begin with readiness (what does it look like ? is it hard or stiff or does it run ? etc.). Instruments such as time allocation studies, useful as they are as indicators of the range of activities and claims on labour, make invisible whatever it is that women themselves see themselves as allocating or conserving. In Huss-Ashmore's case, women collect wild vegetable proteins not because they are a preference food nor because there is nothing else available but because women wish primarily to conserve fuel. The difficulty does not lie in using the measurement units which make sense within the rationality of the referent user but in actually getting someone to do so. Researchers and extensionists alike are trained in the concepts of scientific agriculture and these .concepts may have no equivalents in the knowledge system of the woman while the woman is trained in the concepts of her indigenous knowledge system and may have no way of apprehending the significance (even if the literal meaning can be translated) of the concepts used by the researcher and extensionist. This has little to do with any differences in the ethnic background of the actors and a great deal to do with the difficulty of articulating the rationality of one system in the terms of the rationality of another. Northern Zambia The fact that local vegetables and fruits form an important part of the diet is well-established and there are even a few research programmes investigating the more important species (MAWD 1983). What is not so readily accepted is that these may have characteristics