You send your list of references without being asked. It's not necessary to send your references to every potential employer. For one reason, you could inundate your references with calls, and they won't even be prepared by knowing what position you've applied for.

Is it OK to use someone as a reference without asking?

Your references should be people you have worked for or worked with. Don't use someone as a reference without asking them first. Do not assume your favorite teacher or former supervisor will give you a reference. Always ask for permission first and ask far enough in advance so they have enough time to say yes or no.

Are references usually contacted?

Essentially, yes. While it's true that not 100% of Human Resources (HR) departments will call your references during pre-employment screening, many do. ... The references you provide to employers may be contacted about your employment history, qualifications, and the skills that qualify you for the job.