The development of scientific and quantitative reasoning skills in undergraduates majoring in science, technology, engineering, and mathematics (STEM) is an objective of many courses and curricula. The Biology Department at James Madison University (JMU) assesses these essential skills in graduating biology majors by using a multiple-choice exam called the Natural World-9 (NW-9). NW-9, comprised of measures of Quantitative and Scientific Reasoning, contains items developed by faculty at JMU to assess the impact of the General Education program on the development of scientific and quantitative reasoning skills in a content-independent manner. We discuss methodology we used to involve faculty in determining the generalizability of NW-9 to assess the objectives of the biology curriculum and setting standards to interpret student achievement on NW-9. Student performance on NW-9 identified both strong and weak areas in our instruction and suggested that our biology faculty needs to reevaluate methodology for teaching students how to interpret and analyze data. More important, we can close the assessment loop by allowing faculty to participate in the assessment process and meaningfully reflect on student assessment results. (Contains 2 tables and 1 figure.)