VET Teachers’ Professional Development at Work: Validation of a Measurement Instrument

Since the world is changing rapidly, the importance for teachers to continue their
professional development after their basic teacher training grows. The workplace
appears to be the preferred context for teachers’ professionalization (Postholm,
2012). Workplace learning of teachers takes place when teachers participate in
professional learning activities within the school. The Teachers’ Professional
Development at Work survey (TPD@Work) by Evers et al. (2016) measures
participation in these learning activities. The instrument had been tested and
validated in Dutch primary and secondary education, as well as among teacher
educators in higher education. It might also be useful in vocational education and
training (VET). Professional development activities of VET teachers are currently not
monitored or evaluated in most countries (Cedefop, 2016). A comprehensive
validated instrument for measuring VET teachers’ workplace learning activities is
lacking. The first aim of this study was to test the factorial structure of the
TPD@Work survey among a sample of Dutch VET teachers. Additionally, the second
aim was to assess the construct validity of the instrument, since teachers’
professional development cannot be measured directly (Gravetter & Forzano, 2012).
Construct validity was assessed in terms of convergent validity (when an instrument
shows positive and rather high associations with instruments that are intended to
study theoretically similar concepts), divergent validity (when a construct shows low
associations with a theoretically unrelated, or weakly related, construct) and
predictive validity (when the measurements of the TPD@Work survey predict
certain behaviour). A thorough literature search led to relevant existing
questionnaires for validity assessment, which were added to the measurement
instruments. A quantitative, cross sectional survey study was executed (N = 142).
The results of a confirmatory factor analysis indicate that the six-factor model of the
TPD@Work survey holds among a sample of Dutch VET teachers. In addition, all
subscales show sufficient to good internal consistency. Furthermore, correlation
tests and regression analysis confirm both convergent validity (with similar
workplace learning instruments), divergent validity (with an instrument to measure
emotional demands) and predictive validity (with an instrument measuring
innovative behavior). Therefore, the instrument is validated in the context of VET
and is recommended to measure workplace learning of VET teachers. This helps
monitoring and evaluating professional development activities, for example by
human resource departments or team managers of a VET institution, and indicating
opportunities to further improve quality of teachers and education. The TPD@Work
survey can also be used as a valid instrument to conduct further scientific research
into workplace learning of VET teachers.