You should arrange a meeting with your line manager and explain that you are unwilling to do the work to the deadline requested, with the resources available, because the work could not be relied upon. You could ask for more time to complete the work to the required standard, or ask for the work to be outsourced. This would have the added benefit of enhanced objectivity. The process of clarifying the intended use of the information and expressing your concerns regarding its reliability is likely to enhance your credibility. You could suggest that your line 12 manager discuss the issue with the president or other members of the board, as appropriate.