This study was designed to explore the validity of scores from a select-and-fill-in (SAFI) concept map assessment as a measure of 130 undergraduate students' connected understanding of introductory astronomy. Scores from SAFI maps created for this purpose possessed high internal consistency and showed large mean increases from the beginning to the end of the astronomy course. The SAFI map scores exhibited large relationships with scores from direct-instruction multiple-choice examinations and with scores from a relatedness ratings measure, taken together and separately, for students overall and when examined separately by gender. Results provide initial evidence of the validity of scores from SAFI maps as measures of connected understanding of introductory astronomy in ethnically diverse undergraduate students. (Contains 26 references.) (Author/SLD)