Project Summary/Abstract This project aims to determine whether a media-based intervention targeting low- socioeconomic status (SES) preschoolers and their caregivers can improve children's early literacy skills relative to a caregiver-led shared-reading intervention, in line with two NICHD priority areas: (1) effects of technology and media on child development and (2) school readiness in children from low-SES homes. The current proposal is situated in an implementation science framework, aiming to identify barriers to implementing evidence-based practices and adopting strategies to address these barriers and improve outcomes. In prior work, we found that a storybook intervention with explicit print referencing improves children's early literacy skills; however, caregiver adherence is often low. Here, we hypothesize that using educational media may circumvent or diminish barriers and promote adherence, as media may be more readily incorporated into household routines and thus increase child exposure to print references, a key mechanism for learning. This study addresses four specific aims: (1) To determine the extent to which a media-based, caregiver-led early literacy intervention leads to higher adherence among low- SES families relative to an aligned shared reading intervention (and the extent to which the media intervention reduces barriers, which then leads to higher adherence), (2) To determine the extent to which a media-based, caregiver-led early literacy intervention leads to greater improvement in literacy skills of children from low-SES homes, relative to an aligned shared reading intervention, (3) To determine the extent to which effects are mediated by higher adherence (i.e., intervention dose and intensity), and (4) To determine the extent to which two potential moderators (child sex and caregiver self-efficacy beliefs) influence effects of intervention medium. We also explore potential child-, caregiver-, and dyad-level moderators of intervention medium on early literacy skills. This study uses a randomized controlled trial with three conditions: a caregiver-led media-based early literacy intervention, a caregiver-led shared reading early literacy intervention, and a business-usual control. Participants are 450 caregivers and 3.5 to 4-year-olds. Early literacy skills are assessed at pretest and posttest. Social validity of the intervention is measured to test whether the media intervention circumvents barriers. Fidelity of implementation is measured during the intervention. Follow-up visits at three, six, and twelve months tests long-term effects. Aim 1 uses regression models to compare adherence and social validity across conditions, and to predict adherence from social validity. Aims 2, 3, and 4 are addressed via regression models comparing gains from pre- to post-test and two-level growth models examining growth in skills across follow-up time points. This project is innovative as it seeks to understand mechanisms by which usi...