A pronoun is a part of speech including those words that refer specifically to some noun. Writers should strive to be clear in their use of pronouns. [EDIT]
Pronoun use can create problems with clarity and specificity for writers. On-line help can be found here:
A careful writer should pay close attention to the following cautions when using pronouns:
Avoid the use of pronouns when you are including multiple people of the same gender in the same sentence.
Use “it” cautiously. Prefer the use of “it” only in sentences that include the noun referred to by “it.”
Use “they” cautiously. Avoid referring to some hypothetical “they”; instead, prefer the use of the actual people or group to which you are referring.
Use “this” and “which” cautiously as well. Both can contribute to sentences that are unclear.
Restrict the use of “you” to actual references to the second person, usually a reference directly to the actual reader. Do not shift carelessly between third person and second person.