Julie Horrocks

Chair
Professor, Statistics
Email: 
jhorrock@uoguelph.ca
Phone number: 
519-824-4120 x56556 or 53291
Office: 
MacNaughton 437 or 518

Part of my research is in developing and applying statistical models for data that arise in medical research.  These data usually involve an element of time, so are either longitudinal or survival data. Missing values are usually present and special techniques are required.

Another branch of my research is statistical models that account for spatial correlation. These models are used in spatial epidemiology and the estimation of animal abundance.

A Masters degree in Statistics can lead to an immediate job or future study. Former students of mine have obtained employment as data analysts at various businesses and institutions, including

  • Bell Business Intelligence
  • Statistics Canada
  • Monsanto
  • Athena Software, Waterloo
  • Sick Kids Hospital in Toronto
  • Robarts Clinical Trials
  • Population Health Research Institute,Hamilton
  • Vividata, Toronto
  • Bridgeport Health
  • Canadian Automobile Association (CAA) 
  • Scotiabank
  • OMAFRA
  • Cetero Research
  • Economical Insurance
  • ING Direct
  • Quantics, Scotland

Professional Designation

Professional Statistician (P.Stat) designation, obtained June 3, 2012.  This is a program of accreditation, offered by the Statistical Society of Canada.  The qualification of P.Stat indicates that the holder has the equivalent of an honours degree in statistics, a minimum of six years of professional experience in the application of statistics, and is bound by a Code of Ethics.

Recent Student Projects/Theses

  • PhD
    • Variable Selection for Spatial Point Process Models (in progress).
    • Survival Analysis with Internal Categorical Time-varying Covariates (2017).
    • Ties Between Event Times and Covariate Change Times in Cox Models (2014).
  • MSc
    • Regression Splines For Longitudinal Data (2016).
    • An evaluation of abundance estimators for sea lamprey using stratified mark recapture data (2015).
    • Ordinal Logistic Regression With Survey Weights (2016).
    • The Effect of Diagnostic Misclassification on Spatial Statistics for Regional Data (2014).
    • Regression Methods for Left-censored Data (2014).
    • Internal covariates in survival analysis (2013).
    • A Comparison of Frailty Regression Models (2012).
    • Methods for Missing Zero-Inflated Data (2012).
    • Statistical Models for Zero-Inflated Longitudinal Data (2011).
    • A Study Of Ties And Time-Varying Covariates In Survival Analysis (2011).
    • Quantifying Family History for Mental Illness (2011).
  • Undergraduate 4th year Independent Research Projects
    • Spatial Analysis of Gonorrhea in Southern Ontario (2016).
    • Network Sampling (2015).
    • Bayesian Models for Lake Huron Whitefish Catch Data with Excess Zeros (2015).
    • Estimating Abundance of Seabirds (2014).
    • Methods for Right-Truncated Data (2013).
    • Bayesian Approaches to Estimating Marine Abundance (2012).

Education

B.Sc. (Mount Allison University), 1980.
B.F.A. (Nova Scotia College of Art & Design), 1986.
M.Math. (University of Waterloo), 1993.
Ph.D. (University of Waterloo), 1999.

Details

  • D Harper, J Horrocks, J Barber, G Bravener, CJ Schwarz, RL McLaughlin. An Evaluation of Statistical Methods for Estimating Abundances of Migrating Adult Sea Lamprey. Journal of Great Lakes Research. Submitted Oct 2017.
  • J Daniel, J Horrocks, Gary Umphrey (2017). Penalized composite likelihoods for inhomogeneous Gibbs point process models. Computational Statistics and Data Analysis. Submitted June 9, 2017.
  • C Keown-Stoneman, J Horrocks, G Darlington (2017). Exponential decay for binary time-varying covariates in Cox models. Statistics in Medicine. Accepted 29Sept 2017.
  • C Keown-Stoneman, J Horrocks, G Darlington (2017). Weibull multi-state models with misclassification. Communications in Statistics – Simulation and Computation. Accepted Aug 14, 2017
  • J Daniel, J Horrocks, Gary Umphrey (2017). Penalized composite likelihoods for inhomogeneous Gibbs point process models. Computational Statistics and Data Analysis. Submitted June 9, 2017.
  • C Keown-Stoneman, J Horrocks, G Darlington (2017). Weibull multi-state models with misclassification. Communications in Statistics – Simulation and Computation. Submitted April 4, 2017. Revision Requested.
  • C Keown-Stoneman, J Horrocks, G Darlington (2017). Exponential decay for binary time-varying covariates in Cox models. Statistics in Medicine. Submitted Nov 28, 2016. Revision requested.
    S Goodday, J Horrocks, C Keown-Stoneman, P Grof, A Duffy. Repeated salivary daytime cortisol and onset of mood episodes in offspring of bipolar parents.  International Journal of Bipolar Disorder. 2016 4:12.
  • C Keown-Stoneman, J Horrocks, G Darlington, S Doucette, A Duffy (2015). Multi-state models for investigating possible stages leading to bipolar disorder. International Journal of Bipolar Disorder.   Feb 24, 2015. 3:5. DOI 10.1186/s40345-014-0019-4
  • X Xin, J Horrocks, G Darlington,. Weighting Methods for Ties Between Event Times and Covariate Change Times, Communications in Statistics - Simulation and Computation. Published online 25 Mar 2015.
  • S Doucette, A Levy, G Flowerdew, J Horrocks, P Grof, M Ellenbogen, A Duffy (2016). Early parent-child relationships and risk of mood disorder in a Canadian sample of offspring of a parent with bipolar disorder: Findings from a 16-year prospective cohort study. Early Intervention in Psychiatry. 10:5, 381-389. Published online 30 OCT 2014, DOI: 10.1111/eip.12195
  • A Duffy, J Horrocks, S Doucette, C Keown-Stoneman, P Grof, A Andreazza, LT Young (2014). Immunological and neurotrophic peripheral biomarkers of risk status and illness progression in high-risk youth:  Understanding neurobiological underpinnings of the early clinical stages in developing bipolar disorder. International Journal of Bipolar Disorder. 2014, 2:4  Published online 31 March 2014. doi:10.1186/2194-7511-2-4
  • J Horrocks, M Rueffer, D Gillis, S Wong, D Hamilton (2015). Estimation of Abundance from a Correlated Binary Time Series. In  Cojocaru, M., Kotsireas, I.S., Makarov, R.N., Melnik, R., Shodiev, H. (Eds.),  Interdisciplinary Topics in Applied Mathematics, Modeling and Computational Science Series: Springer Proceedings in Mathematics & Statistics, Vol. 117. DOI: 10.1007/978-3-319-12307-3_34. INVITED CONFERENCE PAPER.
  • Duffy A, Horrocks J, Doucette S, Keown-Stoneman C, McCloskey S, Grof P (2014). The developmental trajectory of bipolar disorder.  British Journal of Psychiatry. 204: 122–28.
    M Rueffer, J Horrocks (2014). A Bayesian Approach to Estimating Animal Density from Binary Acoustic Transects.  Computational Statistics and Data Analysis, 80(C), 17-25.
  • Duffy A, Horrocks J, Doucette S, Keown-Stoneman C, McCloskey S, Grof P (2013). Childhood anxiety:  An early predictor of mood disorders in offspring of bipolar parents. Journal of Affective Disorders 150 (2), 363-369.
  • Doucette S, Horrocks J, Grof P, Keown-Stoneman C, Duffy, A.  Attachment and temperament profiles among the offspring of a parent with bipolar disorder, Journal of Affective Disorders.  150(2) 522-526.
    X Xin, J Horrocks, GA Darlington. (2013). Ties between event times and jump times in the Cox model.  Statistics in Medicine. 32(14) 2374-2389.
  • AC Buchholz,  J Horrocks,  KA Martin Ginis, SR Bray, BC Craven, AL Hicks, KC Hayes, AE Latimer, MA McColl, PJ Potter,  K Smith,  DL Wolfe. (2012)  Changes in traditional chronic disease risk factors and their relationship with leisure-time physical activity in people living with spinal cord injury.  Applied Physiology, Nutrition, and Metabolism. 37(6):1072-9.
  • KA Martin Ginis, KP Arbour-Nicitopoulos, AE Latimer-Cheung, AC Buchholz,  SR Bray, BC Craven, KC Hayes, MA McColl, PJ Potter,  K Smith, D L Wolfe, R Goy, J Horrocks (2012). Predictors of Leisure Time Physical Activity Among People with Spinal Cord Injury.  Annals of Behavioral Medicine. 44(1):104-118. doi 10.1007/s12160-012-9370-9.
  • A Duffy, J Horrocks, R Milin, S Doucette, G Persson, P Grof (2012). Adolescent substance use disorders during the early stages of bipolar disorder: A prospective high-risk study.   Journal of Affective Disorders.142(1-3): 57-64. doi:10.1016/j.jad.2012.04.010
  • J Horrocks, D Hamilton, H Whitehead. (2011). A Likelihood Approach to Estimating Abundance from Binary Acoustic Transects.  Biometrics. 67(3): 681-690. doi: 10.1111/j.1541-0420.2010.01496.
Teaching History
F2017 Stat*3320 Sampling Theory with Applications
W2016 Stat*2230 Biostatistics for Integrative Biology (with Andrew McAdam, IB)
F2015 Stat*6950 Statistical Methods for the Life Sciences
W2015 Stat*3510 Environmental Risk Assessment
Stat*2230 Biostatistics for Integrative Biology (with Chris Caruso, IB)
Stat*4600 Independent Research Project (co-ordinator and supervisor of 2 students)
F2014 Stat*6761 Survival Analysis
Stat*3320 Sampling Theory with Applications
S2014 Spatial Statistics AARMS Summer School (Dalhousie University, July 21 - August 15)
W2013 Stat*6920 Topics: Advanced Survival Analysis (reading course)
Stat*2230 Biostatistics for Integrative Biology (with Chris Caruso, IB)
Stat*3510 Environmental Risk Assessment
F2012 Stat*6761 Survival Analysis
Stat*4600 Advanced Research Project in Statistics (co-ordinator, supervisor)
W2012 Stat*2250 Biostatistics for the Life Sciences (with Beren Robinson, IB)
Stat*3510 Environmental Risk Assessment
F2011 Stat*3240/6920 Applied Regression Analysis
W2011 Stat*2250 Biostatistics for the Life Sciences (with Beren Robinson, IB)
Stat*3510 Environmental Risk Assessment
Stat*6920 Longitudinal Data Analysis (reading course, 4 students)