Browsing by Author "Potgieter, Marietjie"

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    Assessment of preparedness of first-year chemistry students: development and application of an instrument for diagnostic and placement purposes
    (Southern African Association for Research in Mathematics, Science and Technology Education, 2008) Potgieter, Marietjie; Davidowitz, Bette; Venter, Elsie
    Many universities in South Africa use alternative admissions tests together with results of the Grade 12 examinations for access of placement. These tests focus on academic literacy and mathematical skills and do not provide information about proficiencies in disciplines other than mathematics. The implementation of new curriculum for Grades 10-12 in South Africa generates a need to monitor preparedness of first-year students to align first-year curricula as closely as possible to the content of the new syllabi. The need for a tailor-made instrument to assess preparedness for chemistry at the tertiary level was prompted by the lack of suitable tests with the appropriate focus, depth and coverage for application in the South African context. This paper describes the development and evaluation of a test instrument designed to assess and monitor baseline conceptual understanding in chemistry at the secondary-tertiary interface. The study was carried out with mainstream students at the university of Pretoria and Cape Town (N=513 and 258, respectively). Data analysed using the Rasch measurement model confirmed that the majority of students from both cohorts was reasonably well prepared for chemistry at the tertiary level. The use of the instrument for diagnostic purpose was demonstrated. It was possible to identify gaps in the assumed pre-knowledge of students who have qualified for admission to chemistry at a tertiary level at their respective institutions. Inadequate pre-knowledge was most noticeable in the areas of chemical reactions and electrochemistry. In addition, the instrument also shows promise as a placement tool within programmes. Its predictive ability compares well with non-South African placement tests and with Grade 12 mathematics performance, the latter is widely used for this purpose in South Africa.
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    Grade 12 Achievement Rating Scales in the New National Senior Certificate as Indication of Preparedness for Tertiary Chemistry
    (2010) Potgieter, Marietjie; Davidowitz, Bette
    There has been much discussion on the impact of the new curricula for Grades 10–12 on the preparedness for tertiary studies of the 2009 cohort in subjects such as mathematics, chemistry and physics. Using the Chemical Competence Test that was developed and refined earlier, we have evaluated the proficiencies of incoming students to determine the shifts in preparedness for tertiary chemistry that occurred after students wrote the National Senior Certificate (NSC) in South Africa for the first time in 2008. Data were collected in 2009 for first-time entering students at the Universities of Pretoria (UP) (N = 828) and Cape Town (UCT) (N = 315) and compared with that of students who were educated according to the former National Education curriculum (NATED 550) (2005: NUP+UCT = 776). The raw score results showed a decline in proficiency in all topics, and significantly reduced skills development, with mastery of acids and bases showing the most serious decline. Rasch analysis of the data indicated that a 12 percentage point shift in preparedness occurred in 2009 compared with 2005. The contribution to this shift of a mismatch between the new NSC rating scale and the one used previously was also investigated. The implications of the findings for selection and placement and teaching of first year chemistry courses are discussed.
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    Preparedness for tertiary chemistry: issues of placement and performance of academic development programmes
    (Unisa Press, 2008) Davidowitz, Bette; Potgieter, Marietjie; Mathabatha, S. S.
    The introduction of an outcomes-based curriculum in South Africa together with a new syllabus for physical sciences for grades 10-12, prompted the development of an instrument to monitor conceptual understanding in chemistry at the secondary-tertiary interface. This instrument was used to evaluate placement within different programmes at tertiary institutions as well as improvement in the conceptual understanding of chemistry during the first year of instruction. Comparison of preparedness revealed distinct profiles for proficiencies of mainstream and academic development cohorts, respectively, at the Universities of Cape Town, UCT, and Pretoria, UP, but not at the University of Limpopo, UL, which raises doubts about the placement of students at that institution. Unnecessary duplication of offerings for under-prepared students was found at UP. The academic development programmes at UCT and UP were effective in raising the level of conceptual understanding of students while students in the UL programme showed very little improvement.
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    Preparedness for tertiary chemistry: multiple applications of the chemistry competence test for diagnostic and prediction purposes
    (The Royal Society of Chemistry, 2011) Davidowitz, Bette; Potgieter, Marietjie
    The development of the Chemistry Competence Test was prompted by the extensive curriculum changes in the South African school system after democracy was established in 1994. As chemists, we were concerned that there might be a lack of articulation between secondary and tertiary levels, since we anticipated that curriculum changes would have an impact on the knowledge base and skills development of prospective students. A diagnostic test developed initially to document proficiencies of first-time entering students to South African universities has proved to be a versatile instrument for multiple uses. Apart from monitoring levels of preparedness for tertiary chemistry during a period of systemic change, it has also been used to evaluate institutional placement policies, to identify specific conceptual problems and procedural deficiencies, and to measure conceptual gains over the course of the first year at university. In addition, its application for the prediction of risk of failure in first-year chemistry based on cognitive and non-cognitive variables was demonstrated. All these findings are valuable resources to inform lecturers who are concerned about minimizing the conceptual gap between secondary and tertiary chemistry.
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    Use of the Rasch measurement model to explore the relationship between content knowledge and topic-specific pedagogical content knowledge for organic chemistry
    (Taylor & Francis, 2016-06) Davidowitz, Bette; Potgieter, Marietjie
    Research has shown that a high level of content knowledge (CK) is necessary but not sufficient to develop the special knowledge base of expert teachers known as pedagogical content knowledge (PCK). This study contributes towards research to quantify the relationship between CK and PCK in science. In order to determine the proportion of the variance in PCK accounted for by the variance in CK, instruments are required which are valid and reliable as well as being unidimensional to measure person abilities for CK and PCK. An instrument consisting of two paper-and-pencil tests was designed to assess Grade 12 teachers’ CK and PCK in organic chemistry. We used the Rasch measurement model to convert raw score data into interval measures and to provide empirical evidence for the validity, reliability and unidimensionality of the tests. The correlation between CK and PCK was estimated as r = .66 (p < .001). We found evidence to suggest that while topic-specific PCK (TSPCK) develops with increasing teaching experience, high levels of CK can be acquired with limited teaching experience. These findings support the hypothesis that CK is a requirement for the development of TSPCK; proficiency in CK is, however, not necessarily associated with high levels of TSPCK. [Editor's note: this post-print has been embargoed until January 2018]