9995 = Valid Skip
9996 = Not Reached
9997 = Not Applicable
9998 = Invalid
9999 = No Response

1 = Female
2 = Male
5 = Valid Skip
6 = Not Reached
7 = Not Applicable
8 = Invalid
9 = No Response

1 = January
2 = February
3 = March
4 = April
5 = May
6 = June
7 = July
8 = August
9 = September
10 = October
11 = November
12 = December
95 = Valid Skip
96 = Not Reached
97 = Not Applicable
98 = Invalid
99 = No Response

OECD country
0 = No
1 = Yes
2 = Not Applicable

In your home: A room of your own
1 = Yes
2 = No
5 = Valid Skip
6 = Not Reached
7 = Not Applicable
8 = Invalid
9 = No Response

How many in your home: Cars
1 = None
2 = One
3 = Two
4 = Three or more
5 = Valid Skip
6 = Not Reached
7 = Not Applicable
8 = Invalid
9 = No Response

Learning time (minutes per week) - <Mathematics>
99999995 = Valid Skip
99999996 = Not Reached
99999997 = Not Applicable
99999998 = Invalid
99999999 = No Response

Personality: Test Anxiety (WLE)
95 = Valid Skip
96 = Not Reached
97 = Not Applicable
98 = Invalid
99 = No Response

What is the <highest level of schooling> completed by your mother?
1 = <ISCED level 3A>
2 = <ISCED level 3B, 3C>
3 = <ISCED level 2>
4 = <ISCED level 1>
5 = She did not complete <ISCED level 1>
95 = Valid Skip
96 = Not Reached
97 = Not Applicable
98 = Invalid
99 = No Response

What is the <highest level of schooling> completed by your father?
1 = <ISCED level 3A>
2 = <ISCED level 3B, 3C>
3 = <ISCED level 2>
4 = <ISCED level 1>
5 = He did not complete <ISCED level 1>
95 = Valid Skip
96 = Not Reached
97 = Not Applicable
98 = Invalid
99 = No Response

In the last two full weeks of school, how often: I <skipped> a whole school day
1 = None
2 = One or two times
3 = Three or four times
4 = Five or more times
5 = Valid Skip
6 = Not Reached
7 = Not Applicable
8 = Invalid
9 = No Response

Number of <class periods> required per week in <test language>
995 = Valid Skip
996 = Not Reached
997 = Not Applicable
998 = Invalid
999 = No Response

Highest Education of parents (ISCED)
0 = None
1 = ISCED 1
2 = ISCED 2
3 = ISCED 3B, C
4 = ISCED 3A, ISCED 4
5 = ISCED 5B
6 = ISCED 5A, 6
95 = Valid Skip
96 = Not Reached
97 = Not Applicable
98 = Invalid
99 = No Response

Grade Repetition
0 = Did not repeat a <grade>
1 = Repeated a <grade>
5 = Valid Skip
6 = Not Reached
7 = Not Applicable
8 = Invalid
9 = No Response

Number of school changes
0 = no change
1 = one change
2 = two or more changes
5 = Valid Skip
6 = Not Reached
7 = Not Applicable
8 = Invalid
9 = No Response