The objective measurements of quality based on invisible chemical attributes of gum arabic are compared with the assessment done by collectors based on visible attributes with the aim of bringing together the users’ quality requirements and the production and marketing practices of collectors. We find that good quality as defined on field is not always good when measured in laboratory; yet such measures can help target different market niches. Moreover, improving quality on field increases the likelihood of obtaining chemically good gum. We also investigate determinants of supply by collectors and traders of two quality attributes namely size and cleanliness of gum nodules. Quality supply is influenced by harvest and post-harvest knowledge and practices, environmental factors and market factors including the behaviour and experience of traders and price.