In the Tell ';n'; Show method of creating effective presentations, you tell you point, then you show it. So, each point requires some validation, some evidence. Which validation you choose may depend on your audience. Some people want hard data, others want to know what the competition is doing, and still others may want the advice of an expert. A story that conveys a poignant situation may be effective. Sometimes, all you need is an image to show what you';re telling. If you say that the copier you sell fits on a small table, a photograph will suffice.
Knowledge workers carry out these processes by taking into account multiple inputs (generally a wide set of unstructured data and information) to perform difficult tasks and make complex decisions among multiple possible ways of doing the work, each one implying different levels of risk and possible benefits. They are dependent on individuals and it is not possible to automate them. One example of a knowledge process is "Marketing a new product". The same steps are followed each time a new product is launched (benchmarking competitors, deciding pricing strategy, planning promotion, etc...), but it is the experience, knowledge and intuition of the people that drive the process to success.