Choose which forecast model is the most relevant to be used, from a range of qualitative and quantitative ones available. <br/>Qualitative models - Used where data is scarce. For example:<br/>- Consumer or user survey<br/>- Panel of executive opinion<br/>- Salesforce composite, built up from internal areas<br/>- Delphi<br/>- Bayesian decision theory<br/>- Product testing/Test marketing.<br/>Quantitative models - Used when there is a base of historical data to draw on. For example:<br/>- Time series analysis<br/>- Causal techniques.<br/>