Because a personal statement is unlike other documents you write in college, many students struggle with understanding the fundamentals of its definition. First off, don’t let the term itself confuse you—some application materials will use other terms such as “personal essay,” “reflective essay,” “statement of purpose,” or “narrative.” Regardless of the term used, such essays are defined by their comment elements, as detailed below.
One of the best extended definitions of the personal statement I’ve seen appears on a website from the Fellowships Office at Bryn Mawr (see the article "Advice from Fellowship Foundations [1]"). Below I offer a condensed version adapted from that website.
A personal statement is:
A personal statement is not:
Of course, nuances to this definition may be added based on the circumstances. For instance, at times an application might require three different essays with highly specific parameters, and perhaps one of these essays involves a personal narrative while another poses you a philosophical question to answer. Always look to the application itself to determine the degree to which the definitions above apply, and know that when there is a series of questions in an application at least one of them is usually designed to elicit a personal essay from you.
To further help you in defining the basics of the personal statement, I recommend these two sites:
Links
[1] http://www.brynmawr.edu/fellowships/advice/personal_statements/foundation_advice.html
[2] http://ri.search.yahoo.com/_ylt=A0LEVjVnZoRWnusAZKEPxQt.;_ylu=X3oDMTByOHZyb21tBGNvbG8DYmYxBHBvcwMxBHZ0aWQDBHNlYwNzcg--/RV=2/RE=1451546343/RO=10/RU=http%3a%2f%2fwww.brynmawr.edu%2ffellowships%2fdocuments%2fPERSONALSTATEMENTWORKSHEET.doc/RK=0/RS=LSDDvnxI0OIQSE2hPyvJNa5kf7Y-
[3] http://www.wpi.edu/Academics/FS/personal.pdf