Measurement Invariance and Convergent Validity of Scores on the Teacher's Motivation Assessment for Coaching (T‐MAC): Coaching History and Years of Teaching Experience

ABSTRACT Teacher coaching has emerged as an important approach to improving teaching practices. The Teacher's Motivation Assessment for Coaching (T‐MAC) was developed to measure teachers' motivation to receive coaching through three subscales: Perceived Benefits, Psychological Reservations, and Practical Reservations. This study examined two major sources of validity evidence for T‐MAC scores, including validity evidence based on internal structure using multiple‐group confirmatory factor analysis (MG‐CFA) and validity evidence based on correlations with related variables among a national sample of 483 PreK‐12 teachers. Tests of internal structure validity demonstrated strong factorial invariance (equivalency in meaning) of teachers' T‐MAC scores across two extant variables in the coaching literature, including coaching history (participated in one or more coaching sessions vs . never participated in coaching) and years of teaching experience (less than 10 years vs . 10 or more years). Tests of validity evidence based on associations with related variables supported moderate‐to‐strong convergent and divergent validity evidence of teachers' T‐MAC scores with several established theoretically relevant constructs. Collectively, the MG‐CFA results provided evidence that the T‐MAC and its subscales demonstrated acceptable model fit and measurement invariance, supporting the validity of the scores among PreK‐12 teachers. Results are discussed in terms of the potential utility of the T‐MAC as one tool for better understanding teachers' motivation, inform coaching practices, and facilitate coaching initiatives.