The purpose of the addendum is to document the findings from the Year 2 student achievement analyses of a teacher-level randomized experiment, which was designed to examine the implementation and impact of a scalable version of the 2-year MyTeachingPartner Secondary (MTP-S) program as part of a federally-funded Education Innovation and Research (EIR) project. Due to COVID-caused delays, we were unable to include findings about the impact of MTP-S on Year 2 student achievement in the final report produced at the end of the EIR project (Wayne et al., 2023). With the support of a grant from the William T. Grant Foundation, we were able to complete the collection and analyses of Year 2 student achievement data presented in this addendum. Similar to the Year 1 student achievement findings presented in our EIR final project report, the Year 2 student achievement findings did not reveal any significant program impact on students' math or English language arts achievement at the end of the 2-year program. Findings from this study need to be interpreted with caution given study limitations resulting largely from the influence of the pandemic.