for an indicator and comparing its values across education systems. In the case of some education The statistics in this report represent estimates based on samples of teachers and principals, rather than question. Consequently, it is important to measure the degree of uncertainty of the estimates. In TALIS in a manner that reflects the uncertainty associated with the sample estimates. From an observed sample statistic and assuming a normal distribution, it can be inferred that the corresponding population result Differences between sub-groups along teacher (e.g. female and male teachers) and school characteristics (e.g. schools with a high concentration of students from socio-economically disadvantaged homes and significantly different from 0 at the 95% level. In the case of differences between sub-groups, the standard error is calculated by taking into account that from 0, leading to smaller estimates of standard error as compared to estimates of standard error calculated for the difference between independent sub-samples.