An application of multilevel modelling techniques to the longitudinal study of student progress in a modular degree course

This thesis presents a longitudinal study of undergraduate achievement within a\ud modular first degree course, analysing the academic records of a cohort of students who\ud graduated from the Modular Degree Programme at Oxford Brookes University. Multilevel\ud models are fitted to the marks achieved by members of this cohort in each module taken.\ud Level 1 units are individual module entries, nested within occasions within individual\ud student's programmes. These models were fitted by maximum likelihood and used to study\ud the effects of both student and module characteristics on performance. The effects of these\ud factors on mean marks, on the consistency of students performance and on the variation\ud between students were studied by including complex variation at level 1 and random effects\ud at student level in the models. In addition, individual progress charts were fitted, showing\ud how patterns of progress vary from one student to another.\ud Reviewing the hierarchical structure, it was found that a more complex, crossclassified\ud structure is needed to represent the data accurately. This recognises that individual\ud module entries are clustered within modules, as well as within students. Fitting large\ud multilevel cross-classified models is computationally difficult, however newly developed\ud MCMC estimation techniques allowed a model based on the more complex structure and\ud including random effects and complex variation to be fitted. This analysis shows how MCMC\ud estimation techniques can be used to fit a large cross-classified multilevel model,\ud incorporating random effects and complex variation. The results obtained describe students'\ud progress over the period of their degree course and measure the effects, other things being\ud equal, of factors such as assessment methods, age and subject on mean levels of achievement,\ud consistency of performance and the variation between students, providing a model for future\ud studies of achievement within a modular framework

Incidence of and risk factors for perineal trauma: A prospective observational study

Background: Our aim was to describe the range of perineal trauma in women with a singleton vaginal birth and estimate the effect of maternal and obstetric characteristics on the incidence of perineal tears. Methods: We conducted a prospective observational study on all women with a planned singleton vaginal delivery between May and September 2006 in one obstetric unit, three freestanding midwifery-led units and home settings in South East England. Data on maternal and obstetric characteristics were collected prospectively and analysed using univariable and multivariable logistic regression. The outcome measures were incidence of perineal trauma, type of perineal trauma and whether it was sutured or not. Results: The proportion of women with an intact perineum at delivery was 9.6% (125/1,302) in nulliparae, and 31.2% (453/1,452) in multiparae, with a higher incidence in the community (freestanding midwifery-led units and home settings). Multivariable analysis showed multiparity (OR 0.52; 95% CI: 0.30-0.90) was associated with reduced odds of obstetric anal sphincter injuries (OASIS), whilst forceps (OR 4.43; 95% CI: 2.02-9.71), longer duration of second stage of labour (OR 1.49; 95% CI: 1.13-1.98), and heavier birthweight (OR 1.001; 95% CI: 1.001-1.001), were associated with increased odds. Adjusted ORs for spontaneous perineal truama were: multiparity (OR 0.42; 95% CI: 0.32-0.56); hospital delivery (OR 1.48; 95% CI: 1.01-2.17); forceps delivery (OR 2.61; 95% CI: 1.22-5.56); longer duration of second stage labour (OR 1.45; 95% CI: 1.28-1.63); and heavier birthweight (OR 1.001; 95% CI: 1.000-1.001). Conclusions: This large prospective study found no evidence for an association between many factors related to midwifery practice such as use of a birthing pool, digital perineal stretching in the second stage, hands off delivery technique, or maternal birth position with incidence of OASIS or spontaneous perineal trauma. We also found a low overall incidence of OASIS, and fewer second degree tears were sutured in the community than in the hospital settings. This study confirms previous findings of overall high incidence of perineal trauma following vaginal delivery, and a strong association between forceps delivery and perineal trauma. © 2013 Smith et al; licensee BioMed Central Ltd