The majority of my clients are graduate students whose data can only be analyzed through advanced statistical methods. Graduate students in competitive programs rarely have the time or opportunity to take large numbers of statistics classes in addition to their required classes. For such students it is often preferable to hire a statistical consultant who has training and experience with the analyses required. Attempting to analyze data using unfamiliar statistical methods can take weeks or months and still lead to incorrect results. Hiring a consultant ensures correct results in a matter of days.
Hiring a statistical consultant is a perfectly ethical practice. Statistical methods are complex and constantly evolving. As such, academic researchers commonly hire statistical consultants to assist with complex analyses. Doctoral students working on their dissertations often hire statistical consultants for the same reasons. In fact, many of my clients decided to hire a statistical consultant on the advice of their advisers. To ensure that hiring a statistical consultant will not violate the rules of a particular client's academic program, I require a signed letter from the client's committee chair prior to beginning a project.