Decisions are based on information about different choices and their consequences. It might be difficult to make a decision when this information is uncertain. In collective decision, the same information could be perceived and treated differently by various decision-makers. In this case, in emergency situations, people could however reach a compromise and make a decision under time pressure. In non-emergency situations, decision-makers usually tempt to delay decisions, as it is observed in pharmaceuti- cal R&D projects, which are particularly uncertain, risky, long, and expensive. The subject of this study is the identification of the causes of delays and bias in collective decision-making under uncertainty, in non-emergency situations. In order to better understand the decision-making process, we need to understand the notion of uncer- tainty first. We propose a new definition of uncertainty that includes both subjective and objective aspects contributing to uncertainty identification, taking into account the human factors. This definition leads us to a typology of uncertainty factors with three main classes: subject, object, and context. We review how decision-making process is defined in the literature. Based on interviews results, we then present a description of the decision-making process in drug development. We explain which bias could intervene in this process. We propose some good practices in decision-making un- der uncertainty, in order to make decisions more effectively and quickly and to adopt proactive practices instead of reactive ones.