During this time, most graduate students are busily wrapping up their last laboratory rotations and thinking about which one to choose. Some students have an easier time deciding which lab to join, but other students such as myself have a harder time making this decision. Committing to a lab is especially daunting when you start considering the great implications of this decision, not only during your PhD studies, but also in your future career in general. Since many of us are in this position, I think it is of great importance to have a few considerations when deciding which lab to join.
Before even starting to consider which lab you will fit into, it is crucial to know yourself first. Ask yourself as many questions as you can think of at this point. What areas of research are you most interested in? What are your career goals? Would you rather do research from 8am-5pm or have a more flexible work schedule? Are you comfortable having a high level of independence in the lab or do you require more guidance? The list can go on and on, but once you feel confident that you know yourself then you should determine which lab is a good fit for you.
Finding a good mentor is perhaps the most important factor involved in your decision to pick a lab. There are certain qualities that every student should look for in a mentor, such as respect and trustworthiness. Your mentor should recognize that you are more than just an extra pair of hands and should respect your interests as a student. Additionally, you should also feel reassured that your mentor will do as s/he says and give you credit for the work you do. Beyond the common qualities for a good mentor, there are additional mentorship qualities that will greatly vary depending on the needs of the student. Here is when knowing yourself can come in handy, as it will help you to determine which mentorship style is right for you. Make sure to revisit mentors from previous rotations and talk about their expectations of you as a graduate student and determine whether these expectations are feasible. Another important aspect to keep in mind is the mentorship record of the PI: Have previous students graduated in a reasonable amount of time? How many publications did they obtain and how many are first authored? Does the PI encourage students to write their own grant? Does s/he support the research ideas of the students? Etc.
Although choosing a mentor is important, you must also consider the lab environment. As graduate students in the process of learning, we will often seek help from fellow lab members. For this reason, we would want lab members who are not only capable in their laboratory and have analytical skills, but who are also willing to help. You should feel comfortable interacting with the other lab members because you will spend a great amount of time together in the lab. In accordance with the self-reflection you have done, you should be capable of identifying a lab environment that best suits you. Keep in mind that lab environments are fluid so do not base your decision to join a lab solely on the great lab members. Some of the post-docs, technicians, and graduate students that serve as your mentors can always leave but your PI will always be constant.
The last main factor to consider when picking a research lab is your research interest. This is obviously important because you have to be motivated by your research project in order to complete your PhD; however, I consider it to be the least important factor because your research interest might change over time. I believe that any project can become interesting and worth pursuing once you become fully invested in it. You should also remember the nature of research in its ability to change over time and take you into exciting directions. On the other hand, a project that was originally groundbreaking or novel might disappoint you--especially if it is not feasible to complete during your PhD and you spend years troubleshooting the methodology. I would like to add that as far as I know, students do not switch their labs because their project is uninteresting. It is more likely that they were frustrated because their projects were not progressing and/or they did not receive the support from their mentors to overcome this.
So as you consider which lab to join, try not to become too overwhelmed by this decision. If necessary, take some time off to think about it or do an additional rotation. However, always remember that there is no such thing as the perfect lab--there will be pros and cons for each lab and you must decide what factors are more important. Talk to the PIs, lab members, and other students and take into account their insights as well as your own experiences. At the end, if you are still unsure of what lab to choose (because they are all so great!) then you might have to follow your instinct in order to make this decision.