The authentic research experience, which provides students with meaningful collaborative research opportunities designed to promote discovery and innovation under the guidance of mentors, is increasing as a way to attract and engage students in STEM fields. However, despite the increase in authentic research experiences offered to students, there has been little research, particularly at the high school level, investigating students' attitudes about themselves as researchers. To address this need, we developed a theory (or construct) for how high school age students self-identify as researchers and a companion survey to measure their identity. After three iterative development cycles, 823 high school students from diverse backgrounds were administered the 12-item survey, the Researcher Identity Survey-Form G (RISG). The partial credit Rasch model (1960/1980) was used to analyze the survey data. The results indicate that the survey identifies and locates high school age students as researchers validly and reliably along an easy to use and interpret scale. The survey holds promise as an important element for use in programs designed to broaden the entryway for students into the STEM disciplines.