Factor in is a commonly used phrase in writing, implying the consideration of a particular element in any decision-making process. It's important to know some synonyms of this phrase to avoid repetition in writing. One of the synonyms is "take into account," which emphasizes the importance of considering a factor before reaching a conclusion. Another synonym is "bring into play," which implies that a specific element can affect the decision or outcome of an event. Additionally, "include" can replace "factor in" to convey the comprehensiveness required to make a sound judgment. Overall, using these synonyms can add variety to your writing and convey your ideas more effectively.