If your project becomes a poster, proceedings paper, journal article or any published academic work, it is important that proper acknowledgement occurs when appropriate. There is a significant amount of time that a statistician might spend behind the scenes helping the student or faculty member obtain the final statistical analysis. These tasks include a wide range of activities such as developing a data analysis plan, instrument or study design or modification, data re-coding, data management tasks, review of statistics, statistical analysis and interpretation. If the statistician completes one or several of these tasks, proper acknowledgement should be given.
It is important to communicate with and acknowledge all meaningful contributions to your research project. An article from Statistics in Medicine, which gives a nice summary of criteria to consider when acknowledging the work of a statistician.
Another resource for providing guidelines for naming authors for a scientific paper is the Elsevier Authorship Factsheet.
Please review these resources or review the resources with a member of the Biostatistics Core. And, be sure that the doctoral project students explain to their faculty advisors the role of all consultants they worked with and properly acknowledge them.