Who are the relevant stakeholders and why?

Disclose Mistake to Manager and Client?

Robert is working for a consulting company on a marketing project for a client. Robert has been with his consulting firm for less than six months. Robert's responsibilities on the project include measuring the financial impact of a new marketing promotion that his firm has created for the client. To measure the impact, Robert developed a methodology to measure the likely results. This was a relatively sophisticated analysis that the client did not fully understand. However, the client was happy since the first three months the promotion had increased profits by a significant amount. Three months into the promotion, Robert goes through the data and realizes that unfortunately there is an error in one of the spreadsheet cells. Although it was only an error in one cell of a six-tab spreadsheet, Robert knows it could have serious ramifications for the results that have been reported to the client for the first three months. After Robert updated the spreadsheet, he realizes that instead of the original reported amount of profits, the profits attributable to the marketing promotion were only half the amount originally reported. Robert fixed the error, but must now decide how to handle it. Robert, being new to his firm, is still in his probationary period. If Robert discloses the error to his manager, he believes he will look incompetent and would likely be let go. Since Robert is the only one who truly understands the spreadsheet, it is very unlikely anyone else would ever figure out the error. If it wasn't mentioned, everyone would just think the promotion was losing its positive impact. Should Robert tell his manager about the error? Should the client be informed of the mistake?