Teachers as well as students often have difficulty formulating good research questions because not all questions lend themselves to scientific investigation. The following is a guide for high-school and college life-science teachers to help students define question types central to biological field studies. The mayfly nymph was selected as the example study organism because they are common in warm humid climates worldwide and are used as key indicators of water quality and stream health. Assessment of students' work should be a logical extension field investigations. Assessment simply using traditional multiple-choice items after research investigations communicates to students that recall of specific facts (declarative knowledge) is important and investigative processes (procedural knowledge) are not important. Assessment of declarative knowledge should not be ignored, but procedural knowledge should be included. Both are important to science literacy. (Contains 3 figures.)