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Inequality in the track allocation

Background information
About this blog
Which definitions do I use?
What does tracking look like?
What do we expect based on theory?
Does it matter for performance?
Does it increase inequality in performance?
Uploaded 27-12-2019.

Stratification (also 'differentiation')

Stratification is whatever a country does to target teaching at specific groups of pupils or students. Stratification can therefore refer to tracking students, but also to informal kinds of tracking (e.g. ability grouping). The different stratification forms are formalized in various degrees. They are, in a descending order of institutionalization: For a more in-depth analysis of the differences in stratification across countries, I recommend Blossfeld, Buchholz, Skopek, and Triventi (2016) Models of Secondary Education and Social Inequality - An International Comparison.

Next to stratification I discuss in this blog also horizontal stratification, a form of stratification often not often considered as such.


In countries that track their students, students are placed in different school types or specific educational programmes in order to receive their education. Or as the OECD puts it: Tracking is done "(...) explicitly by forming groups of students through selection (...), with the aim of serving students according to their academic potential and/or interests in specific programmes." (OECD, 2005, p. 84) In some cases track placement explicitly focuses on ability, for instance by using test scores or a teacher's recommendation. In other cases students sort themselves into tracks; in doing so, it are the preferences of the particular student and the parents that determine a track placement. Furthermore, tracking often arranges students into programmes that are more or less academically or vocationally oriented, hence "tracking, the practice of sorting students into academic or vocational study programmes" (OECD, 2016, p. 233). Tracking does not necessarily split up the various school systems. In a number of countries (e.g. the Netherlands) some schools offer several tracks within a single school building, although the students in the different tracks never attend courses together. For more information on how tracking takes place, please see the blog post Forms of tracking.

In the blog posts Effects on cognitive outcomes and Effects on inequality, I will discuss the effects of tracking.

Educational systems that do not (explicitly and/or formally) track students are called comprehensive systems. Yet, in comprehensive systems, schools might choose to group students on the basis of ability, using ability grouping or streaming. The different types of informal tracking are described below. These informal ways of tracking often serve as a counterpart of tracking, but they are very heterogeneous in form and effect. Since no country tracks pupils/students in primary education, all primary educational systems can be considered comprehensive systems. An educational system is comprehensive up to the point that it tracks its students into the various educational programmes. Some countries start tracking at the beginning of lower secondary school, while others only do so when students enter tertiary education.

In some 'tracking countries', comprehensive schools exist alongside of tracked schools. In German comprehensive schools (Gesammtschule), students take certain courses together with all other students, for instance Physical education and Social sciences, while other courses are tracked as to ability, comparable to the tracked schools in Germany. However, only a small percentage of students attend such a comprehensive school. In the Netherlands, tracking can be postponed for one to three years by attending so-called 'bridge classes' (brugklassen) comprising one or several tracks.

Key publication: Hanushek & Woessmann (2006).

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Course tracking (also curriculum tracking)

In some countries, students of varying ability are allocated to a school with different educational programmes for only a limited number of courses. Course tracking is a mixture of tracking and ability grouping: it is less institutionalized than tracking and always takes place within schools, it does provide the students in the tracked courses with a different curriculum than their peers tend to get. The United States is an example of a country in which the educational system uses course taking. In a great many US high schools it is possible to take Advanced Placement courses offering more advanced curricula. The regular courses can then be regarded as lower track courses. The AP courses often enable pupils or students to already start earning credits for post-secondary/university education.

Key publication: Chiemelewski (2014).

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Ability grouping

Ability grouping is when students, within a school and/or a grade, are put into classes according to ability. Ability grouping is different from tracking, since it is not a formalized characteristic of a country's educational system, but is done by schools at their own initiative. Since ability grouping is not a formal trait, there are also no national regulations concerning ability grouping. This means that (1) the different ability groups offered in a school will result in the same school degree, that (2) the different ability groups have the same state-prescribed curriculum, and that (3) the formal teacher requirements for teaching the various ability groups are the same.

Since students in groups with higher ability levels will most probably progress faster through the curriculum, it is to be expected that even though the formal curriculum is not any different for the various ability groups, the higher ability groups will at the end of the school year probably have done more than the curriculum prescribes. While the lower ability groups will perhaps have not yet completed the prescribed curriculum.

Even though there will be no difference in the formal teacher requirements per ability group, it is very likely that schools will expect teachers teaching the higher ability groups to have more experience or education. Thus, students in the higher ability groups might get the 'better' teachers, and those in the lower ability groups the ones that are 'less good'. In the blog post Effects of ability grouping, I will discuss the effects of ability grouping.

Key publication: Duflo, Dupas, & Kremer (2011).

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Streaming (also differentiated teaching)

Streaming is when within a class a teacher teaches certain students differently or by using different teaching material. Since all the students are in a single class room, they will all receive the same general instruction from the teacher. However, after the general instruction, the teacher may give some students who find the lesson difficult extra instruction, while (s)he gives others who get their work done fast some extra work to do. In fact, a teacher who wants to present everyone in a heterogeneous class of students with challenging curriculum material that is neither too easy nor too difficult, will somehow have to differentiate her/his teaching. Here, I regard streaming as a structured form of differentiated teaching.

This extra instruction or extra work could be in the form of different text books. For instance, the students in class who have difficulty learning might receive easier text books (one-star books) and the fast learners may receive more difficult ones (three-star books). This text book differentiation could be handled in such a way that students remain unaware of who is in which group in order to avoid stigmatization in class.

The OECD often uses the term 'streaming' to mean 'tracking'. But in their definition tracking is between schools, while streaming is within schools (e.g. OECD, 2005, p. 84). In this blog, I use the term 'tracking' for both forms, within and between schools, and 'streaming' as described above.

Key publication: Kulik & Kulik (1992)

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Horizontal tracking (also 'specialisation')

Horizontal tracking is when, at an educational level (for instance during a track, an ability group or a stream), students receive different curricula due to a choice for different fields of studies. Since it is not in all countries that pupils in primary or secondary school choose a field of study, horizontal tracking is more easily explained in a university setting. All university students will, upon completing their studies, receive a university degree. Whatever the case, students receive a degree in something: a degree in Economics, a degree in Physics, etcetera. Even though people may feel one degree is more difficult than the other (Physics being more difficult than Economics), both are still university degrees. Thus within an educational level (a track), we differentiate further as to the field of study.

In some countries, students in secondary school choose either a batch of courses belonging to the same field of study (e.g. The Netherlands and profielen) or choose freely from the available courses (e.g. United Kingdom and A-levels), while in other countries students choose only a limited set of electives in order to study any further topics (e.g. Germany and the Leistungskurs). In all cases, students specialize their knowledge to some extent through a small set of courses. This specialization is often seen as a preparation for post-secondary education in which one makes the choice for a final field of study. However, in some cases a secondary school specialization might limit the post-secondary options for a field, so that an early choice may have prolonged effects.

What I mean by 'horizontal tracking' is often not regarded as tracking in the literature. However, I believe it is another form of tracking. Just like with degrees of different educational levels, people generally take different views of the degrees in the various fields of study and reward them in different ways in the labour market (physics graduates earning more than economic graduates).

The term 'horizontal tracking' is in line with the literature on labour market mismatches, in which vertical mismatches are those between a worker and the job tasks based on the educational level required for the job, while horizontal mismatches are those in which the worker has the right educational level but in a different field of study.

Key publication: I am not aware of papers looking at field-of-study choices as a means of horizontal tracking. Many reseachers have studied the different pay-offs to field-of-study choices, often in tertiary education (e.g. Hastings, Neilson, and Zimmerman, 2013; Kirkebøen, Leuven, and Mogstad, 2014).

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A country, a state or an educational system

In this blog, I use the term 'country' as a synonym for at whatever level the educational system is established: nationally (country), state or any other type of geographical region. For instance, in Germany the individual states decide on their educational systems and thus each state has its own rules and regulations. And also in Belgium and the United Kingdom different states or counties have different educational systems. For simplicity's sake, I will call all of these entities 'countries'.

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