Bridwell-Mitchell, Ebony NMartinez Orbegozo, Eva Flavia2026-06-0920262026-05-132026Martinez Orbegozo, Eva Flavia. 2026. Here Today, Gone Tomorrow: Teacher Stability and Collaborative Relationships for Peer Learning in Schools. Doctoral Dissertation, Harvard University Graduate School of Arts and Sciences.32701849https://dash.harvard.edu/handle/1/42740369Colleagues are part of what makes teachers improve over time, positioning teacher-to-teacher relationships as potential conduits for professional development in schools and raising the question of what features make them ‘learning-inducing’. Through three interrelated papers, this dissertation engages with this question by focusing on an underexplored relational factor—teacher stability—and how it shapes the collaborative relationships through which peer learning may occur. The first paper develops a theoretical model of learning transfer by taking the teacher-to-teacher relation as the unit of analysis. I propose ‘tie activation’—the notion that ties become learning-inducing when two conditions are met: teachers bring different expertise to their relation, and they engage substantively with each other’s professional knowledge. I theorize relational stability as influencing both conditions—in potentially opposite directions—and model how teachers navigate this tension through choices about collaborative work with implications for peer learning. The other two papers offer complementary empirical approaches to explore teacher stability in connection to collaborative work and teacher practice. Both are set in Spain, where the institutional process for assigning teachers to public schools creates variation in stability: some teachers hold long-lasting, permanent assignments (labeled ‘anchored’ teachers) while others rotate annually through provisional assignments (‘transient’ teachers). Employing large-scale survey data from a representative sample of Spanish public-school teachers, one paper finds that teacher stability relates to collaborative engagement, particularly for deeper forms requiring sustained joint work. Notably, collaboration types associate differentially with classroom practices: lighter coordination activities associate with clarity of instruction, while deeper work associates with cognitively activating practices. Drawing on longitudinal qualitative interviews and social network data collected at two points in time, the other paper examines how stability relates to collaborative networks. Deeper collaboration embedded in instruction is rare overall, but shallower collaboration is unequally accessible. Anchored teachers build larger networks mostly through lightweight discussion-based ties to other stable peers; transient teachers’ experiences depend on school context: those in lower-rotation schools collaborate similarly to anchored peers, while those in higher-rotation schools face compounding constraints. Together, this dissertation points toward teacher stability as a meaningful relational factor worth greater attention in research and practice.application/pdfensocial network analysisSpanish public schoolsteacher collaborationteacher peer learningteacher stabilityteacher turnover and rotationEducationEducational sociologyEducation policyThesis or Dissertation2026-06-090000-0002-0393-8067