Results from PISA suggest that, across OECD countries, schools and countries where students work in a climate characterised by expectations of high performance and the readiness to invest effort, good teacher-student relations and high teacher morale tend to achieve better results, on average across countries and particularly in some countries. Even after accounting for socio-economic background and other aspects of the learning environment measured by PISA, the results show that reading performance is positively related to higher values on the PISA index of teacher-student relationship in 10 OECD countries, including the United States, on the index of disciplinary climate in 16 OECD countries, including the United States, and on the index of teacher-related factors affecting school climate in 14 OECD countries, including the United Stales (Table IV.2.13c in PISA 2009 Results Volume IV). It is noteworthy that in no country is there a negative relationship between any of these factors and learning outcomes.