Here’s an example sentence: It’s important to obtain a thorough detailed history that includes an evaluation of the patient’s pain, functional limitations, and prior medications.
Its is a possessive pronoun that refers to a noun appearing earlier in the sentence.
Here’s an example sentence: The key to understanding the value of clinical practice and its predictable impact on patient treatment is objective measurement.
In this sentence, the word its stands in for the term clinical practice.
When you’re just not sure which form of the word to use, substitute the two words it is. If the sentence makes sense, use it’s. If the sentence doesn’t make sense, use its.
Here’s an example:
Despite the widespread use of the procedure, an absence of data comparing monitored and unmonitored postoperative outcomes places its OR it’s efficacy into question. [Substitute the words it is. The sentence doesn’t make sense, so its (no apostrophe) is the correct form of the word.]