References can be divided into two main categories by purpose: academic and professional. An academic reference is typically a formal letter of recommendation for an academic job, a scholarship, or a fellowship. A professional reference is obtained from someone whose name you supply to a hiring manager at the reference-checking stage (or sometimes sooner) in your job search. These people will most likely be called, and they do not need to prepare a written statement.
Professional References
How many?
3 is standard. Occasionally you may be asked for as many as 5.
Whom should you ask?
Former managers who will speak well of you and your work are the best professional referees. They are familiar with your work, as well as how you handle feedback, your level of initiative, and your strengths and weaknesses as a team member. If you are early in your career these can be supplemented with non-managers as appropriate. For a first job out of college, supplementing your manager from the sub shop with a professor is fine. You could include a peer if you need to fill out the numbers, but no more than one (and this person should be a coworker, not a classmate鈥攕o, peer in the lab where you are both employed is okay, random guy who sits next to you in Chem, not so much).
How should you ask?
It is best to ask directly and specifically. If you have any doubts, it is okay to approach a former manager and ask if they would feel comfortable being a professional reference. (What you actually mean is 鈥渨ill you say nice things鈥 and in general the manager will know that, but if you are concerned, you can ask them directly if they would provide a positive reference for you in your job search.)
What information should you give your referee?
Give your referee a copy of the job posting (or the link to the online posting) and your current r茅sum茅. This will help them know what parts of your duties for them will be relevant to the job you鈥檙e applying for, as well as what professional strengths you are highlighting in your application.
What will they be asked?
The questions your references will be asked will vary, but in general they will probably ask about the quality of your work, your strengths and weaknesses, why you left, and whether they would rehire you. They may also ask about your reliability, how well you received feedback, and about how you worked in a team environment.
Do you need to include your current manager?
You do not need to supply your current manager as a reference. In fact, it is standard procedure to ask applicants to give permission before calling their current manager for a reference. If your current manager is aware of your job search and supportive, though, definitely list them. A positive, current reference from a manager is very helpful. However, if you are asked specifically (on an application form or in another way) whether your supervisor(s) from prior jobs聽can聽be contacted, you should always check 鈥測es鈥. That question is not about whether you can facilitate a contact or would prefer they be contacted or even whether it is possible to contact them鈥攊f you check 鈥渘o鈥 the assumption on the part of the prospective employer is that you were fired for cause from that role, and it is a red flag. You should always check 鈥測es鈥 unless you have a very, very good reason not to. The chances that any given reference beyond the names you have specifically supplied will be contacted are low.
When should you supply professional referees?
When asked. There鈥檚 no need to put them on your r茅sum茅; the hiring manager or recruiting professional knows that you have referees and are prepared to supply them on request.
What information about the referees should you supply?
Most applications will have specific instructions around the information that they want, and you should follow those guidelines. You can usually assume you need to gather some combination of the following: name, job title, organization, and relevant contact info. Phone and email is usually sufficient, but some online forms will also ask for postal mailing address, so be sure you have all that information at hand.
Academic References
How many?
Anywhere between 2 and 5鈥攃heck the posting. If the posting only asks for two references, don鈥檛 give five. If it asks for five, don鈥檛 give three. If it asks for 鈥2-3鈥 (which happens reasonably frequently) use your best judgement. Three is better than two if they鈥檙e all excellent and detailed, but two really good ones are better than two good ones and a mediocre one.
Whom should you ask?
Professors who can speak knowledgably about your work and class performance, a supervisor from an academic job you held, or in certain circumstances even an administrator or non-faculty advisor could write an excellent reference.
How should you ask?
You can ask in person, over the phone, or by email鈥攚hatever is the most convenient way to reach them. Before you approach them, even in person or over the phone, you should always prepare a short document that lists:
The goal is to make it as easy as possible for your referee to write your recommendation by giving them a document that lays out all the pertinent information. It is also a good idea to include a copy of your CV or r茅sum茅. When you ask, ask 鈥淲ould you be comfortable giving me a recommendation for X?鈥 This gives someone who wouldn鈥檛 an out, and may prevent you from making a costly mistake in your application.
Can I see the letter?
No. Well, maybe. But not until afterward, and you shouldn鈥檛 ask; it鈥檚 considered impolite.
When should you supply academic references?
Academic letters of reference or recommendation are usually supplied at time of application to a program, fellowship, scholarship, etc.