Successful project design highly relies on understanding consumer needs and preferences. This marketing knowledge is often learnt from purchasing histories, product attribute rating, consumer preference survey, etc. However, it is unavoidable that ambiguity is a concomitant of all these market analysis methods. Particularly, this ambiguity partly comes from consumer preference biases in purchase situations. We will develop a robust decision analysis and making process under uncertainty of consumer preferences, which can be used for (1) doing the sensitivity analysis on consumer preference models statistically assessed and (2) finding an optimal and robust project design strategy with a rather large tolerance with the imprecision of consumer preference assessment. The sensitivity analysis tells how the current project design solutions are vulnerable to any change on used consumer preference models. The robust design strategy recommended by the framework gives a very good solution well acceptable even if ambiguity in consumer preference assessment methods is a major concern in business.