From time to time as a recruiter, when I ask a candidate for references, they give me letters of recommendation from previous employers or other professional acquaintances.
Is that a good substitute? Is it good enough?
Short answer: No!
While it's nice to be able to give an employer a document where someone was willing to recommend you as a great hire… there are multiple reasons that it's generally not accepted as a sufficient form of reference.
Who actually wrote this? It's not uncommon for a previous employer to say "write something up, and I'll sign it". It takes the burden off of them to have to craft something. While it's generally safe to assume they wouldn't sign something they didn't agree with, the letter is not their words and likely a better indication of the candidates own opinion of themselves than the employers opinion of them.
It's easier than being asked tough questions. The previous employer will sometimes be willing write a letter where they can very selectively pick good points to say about the person, rather than express their full opinion. What's not mentioned in a letter of recommendation is sometimes more important than what is.
It probably doesn't address the questions that the potential employer would most like answered. Questions like "would you re-hire this person if you had the opportunity?" are often not addressed in a letter. Similarly, answers to questions like "where could they use improvement?" are also generally omitted. These are some of the most important inquiries that come up in a phone call, that a letter is not likely to address.
It doesn't convey the conviction in the voice. At times, the most telling feature of a reference call is not so much what is said, but how it's said. A previous employer that truly thinks highly of someone, will often emphasize their esteem in how they express their answers. Their regard can be heard in their voice. Conversely, when someone makes statements very weakly, it raises doubts about how much they rally revere the individual. A letter generally doesn't convey the conviction.
Only the best letters will be presented. Clearly, a candidate will only present recommendation letters that speak the most highly of them. While it can be argued that they will only provide references that will only speak highly of them as well, much more can be learned from a conversation than will be learned from the letter. And it's not at all uncommon that references will divulge a broader spectrum of information in the middle of that conversation. A conversation is almost always much more informative than a letter.
So what should you do? While it's fine to present letters of recommendation, it's also important to have references that can be called available as well. In order to give yourself the best chance of making it through the reference checking process, be sure of what your references will say! Ask them… "Since it's a very competitive job market right now, references really carry weight with potential employers. Can you give me an idea of what you would share with them?"
If their response is something along the lines of… "You know I've always valued you as part of our team and your work. I'd be glad to let them know what a tremendous asset they would get in hiring you!" …you've probably got a great ally in your job hunt. However, if they hesitate in their response, or say something like… "I'll let them know what your job was and that you did OK" …you may want to find another reference. The strength of your references matter!
The next time you are asked for references… be sure you're prepared!