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Two things to be cautious of in interpreting these statements.</p>
<p>First, the language varies a little between programs, and time limits are often stated in terms of specific milestones that most outside the program will not consider meaningful. At what point does university A consider you to officially be a “PhD Candidate”, for example? At what point do you enter doctoral study, is it day 1 post-BS or day 1 post-MS? Rarely do you see guidelines clearly stating how long the entire program will take.</p>
<p>Second, most programs allow exceptions to the time limits based on petition. What they do NOT indicate is how easy those petitions are. Some departments will grant an extension 95% of the time - they use the petition process to get rid of those few students who they realize simply will never finish. Other departments are very strict about the time limits and will grant exceptions only for unusual circumstances.</p>
<p>Ultimately, it should not matter that much. Apply to programs, ask potential advisors how long they expect it to take, and make a choice. Departments do not generally set goals that they do not think their admitted students can reach.</p>