Here is what I told her: The word “by” answers the question “How?”—not the question “Why?”
It’s OK to include “by” if you want to provide more specificity about HOW you will teach an objective, as in: “SWBAT paraphrase an article from the NY Times by employing the ‘bubble-wrap-and-underline’ strategy.…” In fact, some districts require teachers to specify what strategy students will use in order to meet an objective, so using “by” can help them do that.
BUT “by” does not answer the question “Why?” so it does not address the purpose of the objective. Therefore you must use “in order to” if you want to convey the purpose. BOTTOM LINE: To write RPM objectives, you must use “in order to.” You can also include “by.” But “by” alone is not sufficient.