Retaining Educators Takes Added Investment Now Act or the RETAIN Act This bill allows a refundable income tax credit for early childhood educators and program directors, school leaders, and mental health services providers in early childhod educational settings that rewards retention based upon the time such educators spend serving students. The bill directs the Secretary of Labor, in coordination with other department heads, to develop and publish, with annual updates, a data series that captures the average base salary of teachers in elementary and secondary schools and of early childhood educators.