Table 1 Variable descriptions

Student variables

 PISA Reading

Continuous

Outcome variable. Ten plausible values for reading literacy

 PISA Mathematics

Continuous

Outcome variable. Ten plausible values for mathematics

 Female

Indicator

 =1 if student is female; Else = 0

 Economics, Social and Cultural Status (ESCS)

Continuous

Composite score based on three indicators: highest parental occupation, parental education and home possessions. Higher value = higher level of economic, social and cultural status

 School year

Continuous

The student’s school year/grade

 Native

Indicator

 = 1 if student was born in the country and at least one parent also born in the country; Else = 0

 Teacher-directed instruction

Continuous

Index—level of teacher-directed instruction style within the student’s English classes; e.g. “The teacher tells us what we have to learn”

 Teacher support

Continuous

Index—level of teacher support within the student’s English classes; e.g. “The teacher helps students with their learning”

School variables

 Disadvantaged school

Indicator

 = 1 if student attends a school in the bottom quarter of the national distribution of the school-level ESCS index (calculated as the average ESCS index among students in a school); Else = 0

 Single sex

Indicator

 = 1 if student attends single sex school; Else = 0

 Student-staff ratio^a

Continuous

Ratio of students to teaching staff in the student’s school

 School size^a

Continuous

No. of students enrolled in the student’s school

 Percentage SEN students^a

Continuous

The proportion of students in the modal grade for 15 years old in the school who have Special Educational Needs (SEN)

 Staff shortage^a

Indicator

Instruction in school is hindered “to some extent” or “a lot” by a lack of teaching staff = 1; Else = 0

 Quality of teaching material^a

Indicator

Instruction is hindered “to some extent” or “a lot” by quality of available educational material = 1; Else = 0

 School sector^a

Indicator

 = 1 if school is voluntary secondary; Else = 0

 Small town/Rural location^a

Indicator

School is located in a rural area or small town (population of 15,000 or less) = 1; Else = 0

 Student behaviour^a

Continuous

Index—behaviour of students in the school. A higher value indicates poorer student behaviour

 Teacher behaviour^a

Continuous

Index—negative teacher behaviour (e.g., absenteeism or resistance to change). A higher value reflects higher perceived hindrance

 Professional development^a

Continuous

Percentage of teaching staff that attended a programme of professional development in the last three months

 Parental engagement^a

Continuous

Percentage of parents that participate in local school governance; e.g. parent council or school management committee