This study is a survey research focusing on experts’ opinions in the area of software development; about the risk that may occur when they use a Waterfall Model in their software development process. Because risk analysis process does not include in the model. Therefore, interesting problem is finding any hidden risk in the model. Structural interviewing and questionnaires are used in the phases of data collection. Samples are twenty-six experts in field of software development and/or software engineering from eight of Thailand’s universities who have at least 3 years experiences in software development and used to develop successfully software. The Delphi Technique is used in this research. Research results are divided into three phases, the first; experts can identify many risks n their development process. The order of the risk in their opinion is 1) the customer requirements step by mean = 4.12, 2) mean = 3.80 in maintenance and 3) mean = 3.69 in test step. Secondly, five rating scale of the risks identified in the first phase questionnaires are weighted by the developers to clarify those risks. And the last as expected by every experts who confirm their opinions
The results indicated that 95% of the specialists mentioned that the highest risk was the negotiation between software developers and the customers. The second risk was on unlimited cost of the project, and undecided customers share the same risk level as.