in other words the causal direction of this association cannot be determined however in more than a third of countries and economies including many that compensate for disadvantage in schools by allocating more teachers to those schools teachers in the most disadvantaged schools are less qualified andor experienced than those in the most advantaged schools figure sometimes the very policies that channel more resources to highneed schools might in fact deter moreexperienced teachers from teaching in these schools where centrally set rules for promotion and mobility of teachers privilege teacher preferences and give priority to more senior teachers and where teachers pay does not vary greatly across schools or across teachers with similar experience and qualifications it appears difficult to avoid attracting a high concentration of the most experienced teachers in the most prestigious schools