The suitability of the DTVP-2 as a measurement instrument for 5 years and 6 months to 5 years and 11 months English-speaking children in South Africa
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Smith, Mariska
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University of the Free State
Abstract
Showing abstract in English
English: As there is limited comprehensive visual perceptual skills test that has been
standardised on a representative South African population, occupational therapists in
South Africa make use of measurement instruments standardised in other countries
to measure children’s visual perceptual skills. A measurement instrument frequently
used by SA OTs, the DTVP-2, is a reliable and valid test for the population on which
the test was standardised. However, the DTVP-2’s suitability is questioned in a crosscultural
setting, specifically the SA population.
The aim of the study was to investigate the suitability of the Developmental Test of
Visual Perception – 2nd edition (DTVP-2) as a measurement instrument for 5 years
and 6 months to 5 years and 11 month English-speaking boys and girls from the City
of Tshwane, South Africa.
A quantitative, descriptive, observational study was conducted. One-hundred and
thirty four (134) study participants were recruited by means of stratified random
sampling from English Language of Learning and Teaching schools located within
the four educational districts in the urban-suburbs of the City of Tshwane. A selfadministered
screening questionnaire was used as a screening method to establish
children’s eligibility for inclusion in the study, as well as for parents/caregiver to provide informed consent. Children of parents/caregivers who returned the
questionnaires were assessed with the DTVP-2. The DTVP-2’s motor-enhanced
subtests were administered according to the prescribed method, while each of the
motor-reduced subtests of the DTVP-2 was administered with an adapted method of
not implementing the ceiling rule.
Results of the study yielded that the SA study sample’s scores differed to the
American normative sample. The position in space- and visual closure subtests
yielded more accurate results when the ceiling rule was not implemented. It was
established that the DTVP-2 was unbiased for gender, with the exception of figureground,
when scored according to the prescribed method. The DTVP-2 displayed
overall acceptable reliability, however the individual subtests of visual closure, visualmotor
speed and form constancy was found to be unreliable. A Rasch analysis
revealed that figure-ground and form constancy of the motor-reduced subtests
measured a single construct and the four motor-reduced subtests of the DTVP-2
exhibited distorted item difficulty and –linearity resulting in misapplication of the
ceiling rule.
It is concluded that the DTVP-2 should be used with caution to measure 5 years and
6 months to 5 years and 11 months English-speaking children’s visual perceptual
skills and care must be taken when interpreting and conveying scores to parents and
other health care professionals. It is recommended that South African occupational
therapists adjust and/or be sensitive in their assessment procedures in order to
inform evidence-based practice.