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Academic Staff

Freedom N. Gumedze

Office: PD Hahn 6.63
Tel: +27 21 650 4783
Email: freedom.gumedze@uct.ac.za

Position: Senior Lecturer

Research Interests: Development and application of statistical methods in health research. Development and extensions of linear mixed models which may be useful for data analysis in the biological sciences. Joint models for longitudinal data, outlier detection and robust estimation in linear and generalized linear mixed models, design and analysis of clinical trials, meta analysis. and Bayesian methods for the analysis of longitudinal data. I collaborate with researchers in cardiology, dermatology, and HIV-AIDS.

Courses Taught

  • STA1006S – Statistics for Mathematical Disciplines
  • STA2030S – Theory of Statistics
  • STA2005S – Linear Models
  • STA2004F – Statistical Theory and Inference
  • STA3030F – Inferential Statistics

Biographical Information

I obtained a BA degree (1993) from the University of Swaziland, BSc (Hons.) (1997), MSc in Mathematical Statistics (1999) and Ph.D. in Statistical Sciences (2009) from the University of Cape Town. In 2005, I was awarded a Commonwealth Scholarship to work on my Ph.D. at Rothamsted Research, UK.

I was appointed lecturer in the Department of Statistical Sciences at the University of Cape Town in 2000. Previously I had worked as an assistant statistician for the Central Statistical Office of the government of Swaziland. I am currently a senior lecturer. I have taught several under-graduate courses and some post-graduate courses offered by the department. I am currently a Student Advisor in the Department of Statistical Sciences.

I am a member of the International Biometric Society and the South African Statistical Association, and currently the Vice President of the South African Region of the International Biometric Society. I served on the South African Medical Association Journal Editorial Advisory Committee during the period June 2002 - January 2003. I am a statistical reviewer for several medical journals and statistical journals.

Publications since 2007

  • Mayosi, B.M., Ntsekhe, M. Bosch, J., Pogue. J,. Gumedze, F., Badri M,Jung, H, Pandie S, Smieja M, Thabane L, Yusuf S. (2013). Rationale and design of the Investigation of the Management of Pericarditis (IMPI) trial: a 2 x 2 factorial randomized double blind multi-centre trial of adjunctive prednisolone and Mycobacterium w immunotherapy in tuberculous pericarditis. American Heart Journal, 165, 109-115.e3.
  • Beach, R.A., Wilkinson, K.A., Gumedze, F. and Khumalo, N.P. (2012). Baseline Sebum IL-1a Higher than Expected and Different Hair Cosmetics Induce Similar Cytokine Changes in Women with Afro-textured Hair. Journal of Cosmetic Dermatology, 11, 916.
  • Beach, R.A., Wilkinson, K.A., Gumedze, F. and Khumalo, N.P. (2012). Sebum Transforming Growth Factor beta1 Induced by Hair Products. Archives of Dermatology, 148(6), 764-766.
  • Khumalo, N.P. and Gumedze, F. (2012). Traction: Risk Factor or Co-incidence in Central Centrifugal Cicatricial Alopecia? British Journal of Dermatology, 167(5), 1191-3.
  • Khumalo, N.P. and Gumedze, F. (2012). The Adapted Classification of Male Pattern Hair Loss Improves Reliability. Dermatology. 2012;225(2):110-4.
  • Gumedze, F. and T.T. Dunne. Parameter estimation and inference in the linear mixed model. (2011). Linear Algebra and its Applications, 435, 1920-1944.
  • Gumedze, F. and Jackson, D. (2011). A random effects variance shift model for detecting and accommodating outliers in meta-analysis. BMC Medical Research Methodology, 11, 1-19.
  • Khumalo, N.P., Jessop, S., Gumedze, F. and Ngwanya, S. (2011). Folliculitis keloidalis nuchea is associated with the risk of bleeding from haircuts. International Journal of Dermatology, 50, 1212–1216.
  • Ntusi, N.B.A, Badri, M., Gumedze, F., Wonkam, A. and Mayosi, B. (2011). Clinical characteristics and outcome of familial and idiopathic dilated cardiomyopathy in South Africa: implications for clinical practice and research. South African Medical Journal, 101 (6), 399-404.
  • Gumedze, F. N., Welham, S. J., Gogel, B.J. and Thompson, R. 2010. A variance shift model for detection of outliers in the linear mixed model. Journal of Computational Statistics and Data Analysis, Vol. 54. No. 9, 2128-2144.
  • Khumalo, N.P., Stone J., Gumedze, F., McGrath E., Ngwanya L. and De Berker, D. 2010. Relaxers damage hair: Evidence from amino acid analysis. Journal of the American Academy of Dermatology, Vol. 62, No. 3, 402-408.
  • Khumalo, N.P., Jessop, S., Gumedze, F. and Ehrlich, R. 2008. Determinants of marginal traction alopecia in African girls and women. Journal of the American Academy of Dermatology, vol. 59, No. 3, 432-438.
  • Mayosi, B.M., Wiysonge, C.S., Ntsekhe, M., Volmink, J.M., Gumedze, F., Maartens, G., Aje, A., Thomas, B.M., Thomas, K.M., Awotedu, A.A., Thembela, B., Mntla, P., Maritz, F. [Late], Blackett, K.N., Nkouonlack, D.C., Burch, V.C.,Rebe, K., Parish, A., Sliwa, K., Vezi, B.Z., Alam, N., Brown, B.G., Gould, T., Visser, T., Magula, N.P. and Commerford, P.J. (2008). Mortality in patients treated for tuberculous pericarditis in sub-Saharan Africa. South African Medical Journal, Vol. 98, No. 1, 29-36.
  • Ntsekhe, M, Wiysonge, C.S., Gumedze, F., Maartens, G., Commerford, P.J. Volmink, J.A. and Mayosi, B.M. 2008. HIV infection is associated with a lower incidence of constriction in presumed tuberculous pericarditis: a prospective observational study. PLoS ONE, Vol. 3, No. 6: e2253. doi:10.1371/journal.pone.0002253
  • Wiysonge, C.S., Ntsekhe, Gumedze, F., Sliwa, K., Blackett, K.N., Commerford, P., Volmink, J.A. and Mayosi, B.M. (2008). Contemporary use of adjunctive corticosteroids in the management of tuberculous pericarditis in Africa: evidence of clinical equipoise. International Journal of Cardiology, Vol. 124, 388-390.
  • Khumalo, N.P., Ehrlich, R. and Gumedze, F. 2007. Hairstyling is associated with scalp disease in African schoolchildren. British Journal of Dermatology, Vol. 157, No. 1, 106-110.
  • Khumalo, N.P. and Gumedze, F. 2007. African hair length in a school population: a clue to disease pathogenesis. Journal of Cosmetic Dermatology, Vol. 6, No. 3, 144-151.
  • Khumalo, N.P., Jessop, S., Gumedze, F. and Ehrlich, R. 2007. Hairdressing and the prevalence of scalp disease in African adults. British Journal of Dermatology,Vol. 157, No. 5, 981-988.

Conference Proceedings

  • Gumedze, F., Welham S. , Thompson, R. and Dunne, T.T. Use of likelihood ratio tests to detect outliers under the alternative outlier model. To appear: Proceedings of the International Conference on Multivariate Statistical Modelling High Dimensional Data Mining (HDM-2008), held in Kayseri Turkey, 19-23 June 2008.
  • Gumedze, F. 2000. Modelling Relationships between Clinical Markers of the Human Immunodeficiency Virus Disease in a South African Population, In Nokoe, S. (ed), Biometry and Quality of Life, SUSAN-IBS Proceedings, International Institute of Tropical Agriculture: Ibadan, Nigeria: 122-137.
  • Gumedze, F. and Juritz, J. 2000. Modelling CD4 Lymphocyte count with generalised linear models, In Nokoe, S. (ed), Biometry and Quality of Life, SUSAN-IBS Proceedings, International Institute of Tropical Agriculture: Ibadan, Nigeria: 138-146.
  • Gumedze, F. and Gule, G. 1993. Fertility Differentials, In Okore A. and Gule G. (eds), Issues in the Demography of Swaziland, UNFPA, 64-71.

Postgraduate Projects

  1. Detection and accommodation outliers in binomial regression models using random effects
  2. Meta analysis of survival data and ROC curves
  3. Statistical analysis of ROC curves with multiple stages
  4. Joint modelling of longitudinal continuous and time to event data with a composite outcome
  5. Diagnostics for joint models for longitudinal data and time to event data