This document outlines the methodology used in a study about teachers' expectations of students' performance in public schools. The study was conducted at two schools, a high school and a university, in Puebla, Mexico. Qualitative research methods were used, including personal interviews with teachers who had over five years of experience teaching English. The interviews were conducted in Spanish using semi-structured questionnaires and were recorded and transcribed. The goal was to understand the social and educational factors that influence teachers' expectations and how those expectations are reproduced.