Measuring socio-economic status

In PISA, several constructs related to socio-economic status have been derived from the student questionnaire. For all these composite variables the internal consistency measured by Cronbach’s alpha is at or above 0.70. Cronbach’s alpha is a measure of internal consistency based on item covariances (Crocker

& Algina 1996). In table 7.1 the constructs are grouped according to their relationship to the three forms of capital outlined above. This classification should be regarded as one possible suggestion, and it is clear that in certain ways the validity of classification could be questioned, as will be touched upon later. However, factor analysis of the constructs also supports the classification presented.

Table 7.1 Classification of constructs in relation to the three forms of capital Cultural capital Social capital Economic capital Parental education Home social capital Home economy

Highest family socio-economic index

Highest family socio-economic index Home cultural possessions

Home educational resources Books at home

Home cultural competence Student’s cultural activity

All the concepts in table 7.1 are measured using composite variables, except

“Books at home”, which is a single variable, and “Parental education”, which is a simple combination of two single items. In the table, the construct “Highest family socio-economic index” appears twice. This is due to the fact that the International Socio-Economic Index (ISEI) used, represents a combination of education and income, and education and income are related to cultural and economic capital, respectively.

Parental education

The student questionnaire contained explicit questions about the parents’

education. It could reasonably be argued that the parents’ education theoretically should be more strongly related to student achievement than the parents’ professions. There are reasons to believe that parents with a high income level, but a relatively limited education, will place less value on education as being important for their children’s working career than parents with a high level of education, but limited financial resources. Parents’

education is strongly related to the concept of cultural capital. In PISA, the ISCED (International Standard Coding of Education) system has been used to make international comparisons possible. The six categories have been translated into the proper terms in all the participating countries.

Highest family socio-economic status

The concept of “Highest family socio-economic index” needs further clarification. The highest family socio-economic index is derived from the parental occupations given in the student questionnaire. These questions are asked about the mother’s profession (the same questions are asked about the student’s father):

What is your mother’s main job? (e.g. school teacher, nurse, sales manager). If she is not working now, please tell us her last main job.

Please write in the job title.

What does your mother do in her main job? (e.g. teaches high school students, cares for patients, manages a sales team). If she is not working now, please tell us her last main job. Please use a sentence to describe the kind of work she does or did in that job.

The classification of the parents’ occupations is done using a system called ISCO (International Standard Classification of Occupations). This is a system designed for classification of occupations across countries. Ganzeboom &

Treiman (1996) developed an algorithm where each ISCO category is related to a numerical value for socio-economic status on the so-called ISEI scale (International Socio-Economic Index). The ISEI index gives a metric for the sum of education level and income level for each occupational category. This has been quantified based on international empirical data. The ISEI scale ranges from 0 to 90, and the level of socio-economic status increases with increasing values. The different profession categories in the ISCO system have been given ISEI values ranging from 16 to 90.

Home cultural possessions

This construct consists of three single items:

In your home, do you have: classical literature (e.g. Shakespeare)?/

books of poetry?/works of art (e.g. paintings)? (Yes or No)

This construct focuses on possessions in the student’s home as a measure of cultural capital. All the possessions are strongly related to the concept of cultural capital, and the construct could be characterised as a very valid measure of this concept.

Home educational resources

This construct consists of these single items:

In your home, do you have: a dictionary/ a quiet place to study/ a desk for study/ text books? (Yes or No).

How many calculators do you have at home? (None, One, Two, Three or more)

This construct focuses on home resources that are directly useful for the student’s schoolwork, and in table 7.1 the construct was classified in the category “Cultural capital”. These aspects of the home environment could be said to indicate an academic orientation, and the construct could therefore reasonably be classified under the label “Cultural capital”.

Books at home

As stated before, this is not a construct, but a single item:

How many books are there in your home? (From None to More than 500) In previous studies, the number of books at home has been shown to be strongly related to student achievement, for example in the Third International Mathematics and Science Study (TIMSS) (Lie et al. 1997). This is the case even though there is no differentiation between different kinds of books. To be consistent with the concept of cultural capital, the type of books should be significant, i.e. popular literature vs. classical literature.

Home cultural competence

The construct “Home cultural competence” consists of three single items:

In general, how often do your parents: discuss political or social issues with you/ discuss books, films or television programmes with you/ listen to classical music with you? ( Never or hardly ever, A few times a year, About once a month, Several times a month, Several times a week).

As the title of the construct indicates, this construct is intended to measure the level of cultural competence in the student’s home. In a later phase of the process of developing constructs, this construct was renamed “Parental Academic Interest”. As is evident, the construct also incorporates a significant element of social interaction and communication between the student and the parents. In this way the construct differs from another construct related to cultural capital that will be presented later, “Home cultural possessions”, which is more distinctly related to “Cultural capital”. The construct “Home cultural competence” could therefore also be said to measure a component of social capital. It could be argued that this construct is not very precisely linked to Bourdieu’s concept of cultural capital. Listening to classical music is the only activity that is a typical indication of cultural capital. By contrast, discussing TV programmes is not a very typical indication of cultural capital in Bourdieu’s sense. This single item is perhaps a better indication of social capital, as defined earlier in the chapter.

Student’s cultural activity

The construct “Student’s cultural activity” consists of three single items:

During the past year, how often have you participated in these activities:

visited a museum or art gallery/ attended an opera, ballet or classical symphony concert/ watched live theatre? (From Never or hardly ever to Several times a week)

This construct focuses on the student’s own cultural activities. All the activities that are included in the construct, are typical activities related to Bourdieu’s concept of cultural capital. Even though the construct clearly focuses on the student’s own activities, there are strong reasons to believe that the tendency among 15-year-olds to attend these kinds of activities is strongly linked to parental preferences and practices. Therefore, it could be argued that the construct is also a proper measure of home cultural capital.

Home social capital

The construct “Home social capital” consists of three single items:

In general, how often do your parents: discuss how well you are doing at school/ eat the main meal with you around a table/ spend time just talking to you? (From Never or hardly ever to Several times a week)

This construct is designed to explicitly measure home social capital. One of the single items “Discuss how well you are doing at school?” particularly relates to the findings of Ho & Willms (1996) as presented earlier in the chapter. They found that discussing school activities and helping children plan their school programmes had the strongest relationship to academic achievement.

Home economy

One construct is used to measure home economic capital. The construct “Home economy” consists of these single items:

In your home, do you have: a dishwasher/ a room of your own/ educational software/ a link to the Internet? (Yes or No)

How many of these do you have at home: cellular phone/ TV/ computer/

motor car/ bathroom?( None, One, Two, Three or more).