Centre for Statistical Consultation​​​​​
Welcome to Stellenbosch University

Prof Daan Nel



Private consultant

E-mail: dgnel@sun.ac.za​

Phone: 021-8083240


Obtained D.Sc. at the University of the Free State in 1972.


Present Research Interests

Multivariate heteroscedasticity, singular spectrum analysis of time series.



Publications in Journals

The h-th moment of the trace of a noncentral Wishart matrix.  D.G. Nel, S.Afr.Statist.J. (1971), 5,41-52.

On the moments of the trace of noncentral Wishart matrices and submatrices. D.G.Nel, S.Afr.Statist.J.       (1972),  6, 93-102.


On some expectations with respect to Wishart matrices. D.G. Nel and D.J. de Waal. S.Afr.Statist.J. (1973),7,



On the matrix differentiation of the characteristic roots of matrices. R.E Bargmann and D.G. Nel        S.Afr.Statist.J. (1974), 8, 135-144.


On the symmetric multivariate normal distribution and the asymptotic expansion of a Wishart matrix.  D.G Nel,  S.Afr.Statist. (1978), 12, 145-159.


On matrix differentiation in Statistics. D.G. Nel, S.Afr.Statist. J. (1980), 14, 137-193.


Model selection, prediction and estimation for Multivariate normal populations. D.J. de Waal, A.J. van der Merwe, P.C.N. Groenewald, C.J. Lombard, D.G. Nel and S.Geisser. S.Afr.Statist.J. (1981), 15, 113-127.)


A predictive approach to the detection of additional information in a Multivariate regression model.  D.G. Nel, D.J de Waal and D.G Marx Commun. Statist.-Theor.Meth., (1984), 13(17), 2119-2132.(Matric-t distribution. Encyclopedia of Statistical Sciences, D.G. Marx and D.G Nel (1985), Vol.5, Eds. N.L.Johnson and S. Kotz, John Wiley and Sons,Inc.,316-320.


A matrix derivation of the asymptotic covariance matrix of sample correlation coefficients. D.G. Nel. Linear Algebra and its Applications. (1985), 67, 137-145.


A solution to the Multivariate Behrens-Fisher problem. D.G Nel and C.A. van der Merwe. Commun.Statist.-Theory Meth., (1986), 15(12), 3719-3735.


A profile analysis for two groups under the heteroscedastic assumption. D.G. Nel.  Commun.Statist.-  Theory Meth,.(1987) 16(12), 3577-3590.


Linear generalizations of various matric-t distributions. C.A van der Merwe and D.G Nel. Commun.  Statist.-Theory Meth., (1987), 16(12), 3665-3682.


A procedure to select a ML-II prior in a Multivariate normal case. D.J de Waal and D.G Nel. Commun.Statist.Sim.Comp. (1988),17(3), 1021-1035.


On the exact distribution of the univariate and multivariate Behrens-Fisher statistics with a comparison of several solutions in the univariate case. D.G. Nel, C.A van der Merwe and B.K. Moser. Commun. Statist. - Theory Meth. (1990), 19(1), 279-298.


Daylength determines departure date of the spotted flycatcher Muscicapa Striata from its winter quarters. O.B. Kok, C.A. van Ee and D.G, Nel. Ardea, 79(1) (1991), 63-65.


A Bayesian approach to the multivariate Behrens-Fisher problem under the assumption of proportional          covariance matrices. P.C. N Groenewald and D.G. Nel, TEST (1993) Vol 2, No. 1, 15 - 28.


A comparison of the significance levels and power functions of several solutions to the multivariate Behrens-Fisher problem. N. de la Rey and D.G. Nel.  S. Afr. Statist. J. (1993) 27, 129-148


 A test to determine closeness of multivariate Satterthwaite's Approximation. A.I. Khuri, T. Mathew and   D.G. Nel Journ. Mult. Anal. (1994) Vol. 51, No. 1, 201 - 209.


Simultaneous detection of shift in means and variances.  B. Flury, D.G. Nel and I. Pienaar. Journ. Amer. Statist. Assoc. (JASA) (1995), Vol. 90   No.432. 1471 – 1481.


Tests for equality of parameter matrices in two multivariate linear models. D.G. Nel.  Journ. Mult. Anal.  (1997), Vol.61, No.1, 29-37.


The decomposition of the Behrens-Fisher statistic in q-dimensional common principal component          submodels. D.G. Nel and I. Pienaar. Ann. Inst. Statist. Math. (1998), Vol.50, No.2, 241-252.


Allometric Extension. S. Bartoletti, B. Flury and D.G Nel. Biometrics. (1999), Vol.55, No.4,1210-1214.


On a Fisher-Cornish Type Expansion of Wishart Matrices.  Chapter 16, p. 223 - 232 in: Innovations in         Multivariate Statistical Analysis. A Festschrift for Heinz Neudecker. D.G. Nel and P.C.N. Groenewald.  Ed. R.D.H. Heijmans, D.S.G. Pollock and A. Satorra. Kluwer Academic Publications (2000), Dordrecht/ Boston/ London.


On the distribution of the estimator of Cronbach's alpha. J.M. van Zyl, H. Neudecker and D.G. Nel         Psychometrika (2001), Vol. 65, No.3, 271 – 280.


A comparison of approximate confidence interval methods for the difference between two independent        binomial proportions.  M. Nel, R. Schall, G. Joubert and D.G. Nel (2002). S. Afr. Statist.J., 36, 77 - 95.


Fluoxetine decreases stereotypic behaviour in primates. C.Hugo, J. Steier, C. Mdhluli, B.H. Harvey, D. du Toit, S. Wolfe-Coote, Daan Nel and D. Stein.  Progress in Neurosycho-pharmacology & Biological Psychiatry 27, (2003), 639 – 643.


A comparison of the accuracy of two methods used by pre-doctoral students to measure vertical dimension. G.A.V.M. Geerts, M.E. Stuhlinger, D.G. Nel, The Journal of Prosthetic Dentistry, (2004) 91, 59 – 66.


Cluster analysis of obsessive-compulsive spectrum disorders in patients with obsessive-compulsive disorder: clinical and genetic correlates. (C. Lochner, S.M.J. Hemmings, C.J. Kinnear, D.J.H. Niehaus, D.G. Nel, V.A. Corfield, J.C. Moolman-Smook, S. Seedat, D.J. Stein) Comprehensive Psychiatry. (2005), 46,14-19.


Obsessive-compulsive disorder and trichotillomania: a phenomenological comparison. C Lochner, S. Seedat, P.L. du Toit, D.G. Nel, D.J.H. Niehaus, R. Sandler and D.J. Stein.  BMC Psychiatry, (2005), 5 :2 DOI: IO.1186/1471-244X-5-2 http:/www.biomedcentral.com/1471-244X/5/2


Rapid screening of the fermentation profiles of wine yeasts by Fourier transform infrared spectroscopy.         H. Nieuwoudt, I.S. Pretorius, F.F. Bauer D.G Nel and B.A. Prior.  Journal of Microbiological Methods.  67 (2006), 248 – 256.


Development, microbiological content and sensory analysis of a spread rich in n-3 fatty acids. A. Dalton, R.C. Witthuhn, C.M. Smuts, P. Wolmarans, D.G. Nel.  Food Research International (2006); 39(5), 559-567.


Exploratory and confirmatory factor analysis of the Multidimensional Anxiety Scale for Children. (MASC) among adolescents in the Cape Town metropole of South Africa.  Dylan Fincham, Johannes Schickerling, Michael Temane, Daan Nel, Winnie De Roover and Soraya Seedat. Depression and Anxiety 0, 1-7, (2007)


The Neuropsychiatry and Neuropsychology of Lipoid Proteinosis. Helena B. Thornton , Daan Nel, Dorothy Thornton, Gus A. Baker, Dan J. Stein  & Jack van Honk , Journal of Neuropsychiatry and Clinical Neurosciences.20:1, (Winter 2008), p86-92.


Depression and anxiety in multisomatoform disorder: Prevalence and clinical predictors in primary care. Muller J.E, Wentzel I, Nel D.G. and Stein D.J. South African Medical Journal; (2008), 98(6), 473- 476.


 Alcohol-Induced Psychotic Disorder: A Comparitive Study on the Clinical Characteristics of Patients with Alcohol Dependence and Schizophrenia. G.P. Jordaan, D.G. Nel, R.H. Hewlett and R. Emsley. Journal of Studies on Alcohol and Drugs. (2009), 870- 876.


Does carbimazole have an effect on I-131 therapy in Graves disease? Annare Ellmann, Nason Lambwe, Daan Nel and Stephen Hough. J Nucl Med. (2009), 50 (Supplement 2):431


Acute renal failure in the medical ICU still predictive of high mortality. DV Friedericksen, L van der Merwe, DG Nel and MR Moosa. South African Medical Journal (2009) Vol.99, No.12, 873-875.


Common singular spectrum analysis of several time series. H. Viljoen and D.G. Nel .Journal of Statistical Planning and Inference,Vol.140,1, (2010) 260-267.


Relationships between drying defect parameters and some growth characteristics in kiln-dried South African grown Eucalyptus grandis poles. P. Mugabi, T. Rypstra, H. F. Vermaas and D.G. Nel. European Journal of Wood and Wood Products (2010); 68: 329-340.


The aetiology of adult burns in the Western Cape, South Africa. David Maritz, Lee Wallis, Elbie van der          Merwe and Daan Nel. Burns (2011) Published online:10.1016/ J Burns. 2010.12.007


Correlation between drying effects, their parameters and the moisture gradient in kiln-dried, (2010) South African grown Eucalyptus Grandis Poles. Maderas Ciencia y Tecnologia 12(3) 199-208.


Effect of kiln drying schedule on the quality of South African grown Eucalyptus grandis poles. P. Mugabi, T. Rypstra, H.F. Vermaas, and D.G. Nel. European Journal of Wood and Wood products (2011), 69: 19-26.


Suitability of auger drill sampling for the measurement of moisture content gradient in kiln-dried   South African grown Eucalyptus grandis poles. . P. Mugabi, T. Rypstra, H. F. Vermaas and D.G. Nel. European Journal of Wood and Wood Products (2011); 68: 329-340.


Alcohol-induced psychotic disorder: brain perfusion and psychopathology—before and after anti- psychotic treatment Gerhard P. Jordaan & James M. Warwick & Daan G. Nel & Richard Hewlett & Robin Emsley (2012) Metabolic Brain Disease 27(1) 66-77.


Predicting mortality and length-of-stay for neonatal admissions toprivate hospital neonatal intensive care units: a Southern African retrospective study. P.T. Pepler, D.W. Uys & D.G. Nel (2012) African Health Sciences, Vol 12, No 2, 166-173.


The effect of nutritional status on outcome in critically ill patients – does body mass index indicate anything?   R. Blaauw, C Blanckenberg and D.G. Nel Clinical Nutrition Supplements 7(1):34–


Inadequate nutrition during the first few days correlates with the increased length of ICU stay: A prospective descriptive study. R. Blaauw, C. Blanckenberg, D. Nel. Clinical (2012) Nutrition Supplements 09/2012; 7(1). PP025-SUN I


Translation and validation of European Organisation for Research and Treatment of Cancer QLQ-CX24 questionnaire into the indigenous African languages of isiXhosa and Afrikaans.  G.C. du Toit and D.G. Nel (2012) South Afr J Gynaecol Oncol, Vol 4 No 2, 59-62.


Fetal heart rate patterns at 20 to 24 weeks gestation as recorded by fetal electrocardiography.  Hofmeyr F, Groenewald CA, Nel DG, Myers MM, Fifer WP, Signore C, Hankins GDV, Odendaal HJ, (2014) The Journal of Maternal-Fetal & Neonatal Medicine, 27, 714-8.


Variation in strength, stiffness and related wood properties in young SoutAfrican-grown Pinus patula.  C.B. Wessels, F.S. Malan, D.G. Nel and T Rypstra. Southern Forests, 2014, 76(1): 37-46.


Probiotics, feeding tolerance, and growth: a comparison between HIV-exposed and nexposed very low birth weight infants. E. van Niekerk, G.F. Kirsten, D.G. Nel, R. Blaauw. Nutrition, 2014, Jun; 30(6) 645-653


Human Milk Oligosaccharides differ between HIV-Infected and HIV-Uninfected mothers and are related to Necrotizing Enterocolitis incidence in their preterm very-low-birth-weight infants.  E. van Niekerk, C.A. Autran, D.G. Nel, G.F. Kirsten, R, Blaauw and L. Bode. J. Nutr. 2014: 8 1227-1233.


A comparison of some methods for the selection of a common eigenvector model for the covariance matrices of two groups. P.T. Pepler, D.W. Uys and D.G Nel. Communications in Statistics- Simulation and Computation.45:8 (2016), 2917-2936: DOI 10.1080/03610918.2014.932801. 0


Probiotics reduce Necrotizing Enterocolitis severity in HIV-exposed infants. E. van Niekerk, D.G. Nel, R. Blaauw and G.F. Kirsten. Journal of Tropical Pediatrics, 2015, 0, 1-10.


Comparison of infant-feeding practices in two health subdistricts with different baby-friendly status in        Mpumalanga province. Van der Merwe S, Du Plessis LM, Jooste H, Nel DG, (2015) South African Journal of Clinical Nutrition; 28(3):121-127.


 Effect of maternal position and uterine activity on periodic maternal heart rate changes before elective       cesarean section at term. Ibrahim S, Jarefors E, Nel DG, Vollmer L, Groenewald CA, Odendaal HJ. Acta Obstetricia et Gynecologica Scandinavica (AOGS) DOI: 10.1111/aogs.12763


Discriminant analysis under the common principal components model, P.T. Pepler, D.W. Uys & D.G.   Nel (2016): Communications in Statistics - Simulation and Computation, 46:6,4812-4827.   DOI:10.1080/03610918.2015.1134568


Cognitive changes in alcohol-induced psychotic disorder.Melany Leonie Hendricks, MA Clinical  Psychology; Melany L. Hendricks, R. A. Emsley, D. G. Nel, H. B. Thornton and G. P. Jordaan  BMC Res Notes (2017) 10:166, DOI 10.1186/s13104-017-2485-0


The association between tuberculosis and the development of insulin resistance in adults with pulmonary tuberculosis in the Western sub-district of the Cape Metropole region, South Africa: a combined cross-sectional, cohort study.  Lauren Philips, Janicke Visser,  DG Nel, Renee  Blaauw.  BMC Infectious Diseases Cognitive (2017) 17:570 DOI 10.1186/s 12879-017-2657-5 


Fetal footlength at delivery as a tool for determining gestation length in non-macerated stillbirths. Geldenhuys E, Coldrey J, Wright C, Nel D, Roberts D, Boyd TK and  Odendaal H. Int J Gynaecol Obstet. (2017).

DOI 10.1002/ijgo.12177.


The barriers that women face when choosing food for their primary school children: A case study in the Western Cape Province, South Africa October 2017, Yolande Smit, S Kassier, Daniel G Nel & Nelene Koen, South African journal of child health 11(3):129-134  DOI 10.7196/SAJCH.2017.v11i3.1292


Staff and student health and wellness at the Faculty of Medicine and Health Sciences,  Stellenbosch University: current status and needs assessment, N Koen, L Philips, S Potgieter, Y. Smit, E van Niekerk, DG Nel & J Visser: South African Family Practice, (2018) DOI: 10.1080/20786190.2017.1396788


Consumer knowledge and use of food and nutrition labelling in South Africa: A cross-sectional descriptive study. Nelene Koen, Edelweiss Wentzel-Viljoen, Daan Nel, Renee Blaauw.  Int J Consum Stud. 2018;1–12.


Regularised Covariance Matrix Estimation under the Common Principal Components Model. P.T. Pepler, D.W. Uys & D.G. Nel (2018):  Communications in Statistics - Simulation and   Computation, DOI: 10.1080/03610918.2015.1040499


 Effects of alcohol, cigarettes, methamphetamine and marijuana exposure during pregnancy on maternal serum alpha-fetoprotein levels at 20-24 weeks' gestation. Odendaal HJ, L Geerts, DG Nel, LT Brink, E Hitchcock, CA Groenewald (2018) J Pediatr Neonatal Care. 2018; 8(1): 00314. DOI: 10.15406/jpnc.2018.08.00314


 Evaluation of nutrition care to adult patients on HAART attending primary healthcare facilities in Mpumalanga.

JF Schiever, J Visser, M van der Merwe & DG Nel (2018) South African Journal of Clinical Nutrition DOI.org/10.1080/16070658.2017.1412183 


The effect of maternal HIV status and treatment duration on body composition of HIV-exposed and HIV-unexposed preterm, very- and extremely low birth weight infants.  Klara Strydom, Daniel Gerhardus Nel, Muhammad Ali Dhansay & Evette Van Niekerk (2018)  Paediatrics and International Child Health

DOI: 10.1080/20469047.2018.1466481


 Four-oil intravenous lipid emulsion effect on plasma fatty acid composition, inflammatory markers and clinical outcomes in acutely ill patients: A randomised control trial (Foil fact) V. Donoghue, G.K. Schleicher, M.G.L. Spruyt, L. Malan, D.G. Nel, P.C. Calder, R. Blaauw (2018) Clinical Nutrition.   DOI: 10.1016/j.clnu.2018.12.010


 Effect of Nutritional Intake on the Body Composition of HIV-Exposed and HIV-Unexposed Preterm and Low Birth Weight Infants. Klara McClunan, Daniel Gerhardus Nel, Muhammad, Ali Dhansay & Evette Van Niekerk BREASTFEEDING MEDICINE, Volume 14, Number 2, (2019), Mary Ann Liebert, Inc. DOI:10.1089/bfm.2018.0113


 Effects of low maternal heart rate on fetal growth and birthweight.  Hein Odendaal, Eduard Kieser, Daan Nel, Lucy Brink, Carlie du Plessis, Coen Groenewald, Maristella Lucchini, William P. Fifer, Michael M. Myers (2019) International Journal of Gynecology & Obstetrics, DOI: 10.1002/ijgo.12873


 Determinants of serum 25-hydroxyvitamin D levels in healthy young adults living in the Western Cape, South Africa, J Visser, K Knight, L Philips, W Visser, M Wallace, DG Nel & R. Blaauw (2019): South African Family Practice. DOI.org/10.1080/20786190.2019.1621047


 The association of Prenatal Alcohol Exposure on the Cognitive Abilities and Behaviour Profiles of 4- year-old children: a prospective cohort study" CA Cluver, W Charles, C van der Merwe, H. Bezuidenhout, D Nel, C Groenewald, L Brink, S Hesselman, L Bergman, H Odendaal (2019), BJOG, An international journal of obstetrics and Gynaecology. DOI: 10.1111/1471-0528.15947


 In utero teratogen exposure and cardiometabolic risk in 5-year-old children: a prospective pediatric Study. J. J. A. De Smidt, H. J. Odendaal, D. G. Nel, H. Nolan, C. Du Plessis, L. T. Brink & A. Oelofse .(2019) The Journal of Maternal-Fetal & Neonatal Medicine, DOI:10.1080/14767058.2019.1692337


 Alcohol use predicts emergency psychiatric unit admission for non-fatal suicidal behaviour  in the Western Cape (South Africa): a case–control study.  Daniel Goldstone, Jason Bantjes, Daan Nel, Jessica Stanbridge & Ian Lewis (2020): International Journal of Psychiatry in Clinical Practice, DOI: 10.1080/13651501.2019.1711419


 Plasma Glutamine Levels in Relation to Intensive Care Unit Patient Outcome. Renée Blaauw, Daan G. Nel and Gunter K. Schleicher (2020) Nutrients 2020, 12(2), 402; https://doi.org/10.1080/13651501.2019.1711419


 Association of socioeconomic status and clinical and demographic conditions with the prevalence of preterm birth. Hein Odendaal, Lucy Brink, Daan Nel, et al (2020) International Journal of Gynecology & Obstetrics (2020)

IJGO13143 DOI: 10.1002/ijgo.13143 


Smoking and drinking habits of women in subsequent pregnancies after specific advice about the dangers of these exposures during pregnancy. H.J Odendaal, D.G Nel, M.H Carstens, M. de Jager, M. Potter, C. du Plessis and C. Groenewald. (2020) South African Medical Journal November 2020, Vol. 110, No. 11, 1100-1104


 Associations of maternal smoking and drinking with fetal growth and placental abruption. H. Odendaal, C. Wright, P. Schubert, T.K. Boyd, D.J. Robbers, L. Brink, D. Nel, C. Groenewald. European Journal of Obstetrics & Gynecology and Reproductive Biology 253 (2020), 95–102)


 The effects of in utero exposure to teratogens on organ size: a prospective paediatric study. J. J. A. De Smidt , H. J. Odendaal, D. G. Nel, H. Nolan, C. Du Plessis, L. T. Brink and A. Oelofse (2020)  Journal of Developmental Origins of Health and Disease doi: 10.1017/ S2040174420001002, 1-10


Consumer knowledge, perceptions, practices and the barriers relating organic foods -Johannesburg, Gauteng Province South Africa. Nina Erasmus, Yolande Smit, Daan Nel & Nelene Koen (2020), ISSN 0378-5254 Journal of Consumer Sciences, Special Edition. Food and nutrition challenges in Southern Africa, Vol 5, 78-97.





Visiting appointments or Scholarships

  • University of Georgia          :September 1973 - March 1974 and January - July 1979.
  • Stanford University              :June - August 1984 and June - August 1995.
  • Indiana University:               June - August 1992 and January – June 1997.
  • Scuola Matematica Interuniversitaria at Perugia, Italy: 23 July -  28 August 1999.


Societies and Committees

  • Fellow of the South African Statistical Association.(SASA)
  • President of the SASA (1982).
  • Member of the working committee on the South African Statistical Dictionary (1984).
  • Associate editor of the South-African Statistical Journal (1982-1984), (1991- 1999).