<Programme> Q1b
1 = Bezirksch, Sekundarsch., Realsch., Obersch., Pro-Gymn. usw.
3 = Maturitätsschule/maturité gymnasiale
99 = Missing

Sex Q3
1 = Female
2 = Male

Mother currently doing Q5
1 = Working full-time
2 = Working part-time
3 = Looking for work or other
8 = Invalid/NA
9 = Missing

Country of birth Self Q15a_a
1 = Test country
2 = Other country
98 = Invalid/NA
99 = Missing

Country of birth Age Q15b
1 = under five years of age
2 = five years of age or more
997 = N/A
999 = Missing

Language at home Q16
1 = Test language
2 = Other languages
99 = Missing

Possessions cell phones Q18a
1 = none or one
2 = two or more
8 = Invalid/NA
9 = Missing

Possessions computers Q18c
1 = none
2 = one
3 = two or more
8 = Invalid/NA
9 = Missing

How many books at home Q19
1 = 0-10 books
2 = 11-25 books
3 = 26-100 books
4 = 101-200 books
5 = 201-500 books
6 = more than 500 books
8 = Invalid/NA
9 = Missing

<ISCED 1>Years Q21
1 = less than five years of age
2 = between five and seven years of age
3 = seven years of age or more
998 = Invalid/NA
999 = Missing

Repeat <ISCED 1> Q22a
1 = No, never
2 = Yes
8 = Invalid/NA
9 = Missing

Attend local Q25a
1 = Tick
2 = No tick
8 = Invalid

Students in Maths Q36
1 = less than 10
2 = between 10 and 25
3 = more than 25
998 = Invalid/NA
999 = Missing

Available at home IC1a
1 = Yes
2 = No
8 = Invalid/NA
9 = Missing

How long using computers Q3
1 = Less than 1 year
2 = 1 to 3 years
3 = 3 to 5 years
4 = More than 5 years
8 = Invalid/NA
9 = Missing

Use often at home IC4a
1 = Amost every day
2 = A few times each week
3 = between 1 per week and 1 per month
4 = Less that 1 per month
5 = Never
8 = Invalid/NA
9 = Missing

Learn Computer IC8
1 = My school
2 = My friends
3 = My family
4 = Taught myself
5 = Others
8 = Invalid/NA
9 = Missing

Learn Internet IC9
1 = Don't know how to use
2 = My school
3 = My friends
4 = My family
5 = Taught myself
6 = Others
8 = Invalid/NA
9 = Missing

age of student
1 = under 15 years
2 = 15 years
3 = over 15 years
9 = Missing

Family Structure
1 = Single parent family
2 = Nuclear family
3 = Other
9 = Missing

Mother White collar/Blue collar classification
1 = White collar high skilled
2 = White collar low skilled
3 = Blue collar high skilled
4 = Blue collar low skilled
9 = Missing

Educational level of mother (ISCED)
1 = lower secondary level of education or less
2 = upper secondary/post secondary level of education
3 = vocational tertiary level of education
4 = theoretically oriented tertiary and post graduate level
9 = Missing

Country of birth
1 = Native students
2 = First-generation students
3 = Non-native students
9 = Missing

Relative time spent on Maths homework
999 = Missing

Minutes of Maths per week
997 = N/A
998 = Invalid
999 = Missing

Language region
1 = German
2 = French
3 = Italian

national schoolprogram
1 = Schulprogramm mit höheren Ansprüchen
2 = Schulprogramm mit mittleren Ansprüchen
3 = Schulprogramm mit tieferen Ansprüchen
4 = Schulprogramm nicht nach Leistungsniveau unterschiedlich
9 = Missing