Table:
type of compulsory schooling controls in the estimator
entry and dropout age fixed effects
entry versus dropout age effects
effect of total mandatory years
effect of total mandatory years

coefficient estimates

fixed effects

entry age = 7
0.010
..
..
..

entry age = 8
-0.029
..
..
..

dropout age = 15
0.003
..
..
..

dropout age = 16
0.013
..
..
..

dropout age = 18
0.028
..
..
..

linear effects

entry age
..
-0.013
..
..

dropout age
..
0.008
..
..

combined effect

mandatory years
..
..
0.010
0.010

additional controls

age fixed effects
yes
yes
yes
yes

cohort fixed effects
yes
yes
yes
yes

birth-province fixed effects
yes
yes
yes
yes

birth province-cohort trends
yes
yes
yes
yes

institutional covariates
yes
yes
yes
yes

individual covariates
no
no
no
yes

labour income controls
no
no
no
yes

labour income 10-piece spline
no
no
no
yes

estimates

statistics

r-squared
0.042
0.041
0.041
0.118

f-test of excluded instruments
11.080
15.180
26.730
26.540

number

observations
477,813
477,813
477,813
473,608

Statement: three different approaches to account for compulsory schooling laws are used.
Question: how many different approaches to account for compulsory schooling laws are used?
Answer: [3]