A Test of Asset-Pricing Models at the Nairobi Securities Exchange

The Capital Asset Pricing Model (CAPM) has for a long time been used to explain the variations in expected return on stocks. However, the discoveries of market anomalies such as the Size, Book-to-Market and the Momentum effects, have greatly undermined CAPM’s ability to explain the expected returns on stocks. These anomalies prompted Fama and French (1993) and Carhart (1997) to propound asset pricing models that captured the effects of these anomalies. This study sought to test whether the CAPM, Fama and French (1993) Three-factor model and the Carhart’s (1997) Four-factor model can explain the returns of stocks traded in the NSE, from a portfolio perspective. The stock returns used in this study were those for the forty eight companies that trade under the MIMS in the NSE, during the period January 2009 to December 2013. Six portfolios that were sorted for size and Book-to-Market were created and used to test the CAPM as well as the Fama and French (1993) Three-factor model. Also, an additional six portfolios that were sorted for size and past performance were constructed to test the Carhart’s (1997) Four-factor model. The data was then analyzed using time series regression analysis and the estimated parameters were tested for significance. This study finds that even though the CAPM has been highly regarded for many years, when tested at the NSE from a portfolios perspective, the evidence in support of it is weak. This study finds that other significant factors exists that were not captured by CAPM, implying therefore that beta is not an adequate measure of risk. Also, as for the Fama and French (1993) Three-factor model, this study finds that it doesn’t quite capture all the factors influencing the returns of stocks traded at the NSE. However, this study finds that the Carhart’s (1997) Four-factor model performs better relative to the CAPM and the Fama and French (1993) Three-factor model, as it was observed to have a better explanatory power of the variation of expected returns of most of the sets of portfolios that it was tested on. The findings of this study will be of great significance to the finance academia and policy makers as it will assist in boosting their understanding of an asset-pricing model that can explain better, the variations in returns of stocks traded at the security exchange. Keywords: Asset pricing Models, NSE, Keny

Investigations of Experiential Cooperative Concept Mapping Instructional Approach on Secondary School Girls’ Achievement in Physics in Nyeri County, Kenya

This study investigated the effects of Experiential Cooperative Concept Mapping Instructional Approach (ECCA) on girls’ achievement in Physics in secondary schools. The study employed Quasi- Experimental Research Design represented by Solomon Four Non-equivalent Control Group Design. Stratified sampling technique was used to select 8 Secondary Schools from girls’ alone and co- educational schools strata drawn from Nyeri County. A total of 334 Form Two students were involved in the study.  A validated Students Physics Achievement Test (PAT) with a reliability coefficient of 0.80 was administered. The experimental group I and III were exposed to ECCA while the conventional Method was used for the control group. Two groups were pre-tested prior to the implementation of the ECCA treatment. After five weeks, all four groups were post-tested using the Physics Achievement Test (PAT). Data was analyzed using ANOVA and ANCOVA at a significance level of alpha (?) equal to 0.05.  The results of the study revealed significant effect on achievement of girls when ECCA was used. However there was a significant effect in achievement on school type in favour of girls’ alone class performing better than girls in co-educational class when ECCA was used. The investigations concludes that ECCA is an effective learning strategy which physics teachers should be encouraged to use in their teaching/ learning process in order to address the current low girls performance. This may create an increased pool of scientific and technical female workers in the area where Physics is a requirement. Key words- Experiential Cooperative Concept Mapping (ECCA), Conventional Methods (CM), Secondary School, Girls’ Achievement, Physics, Nyeri County

Effects of Experiential Cooperative Concept Mapping Instructional Approach on Secondary School Students’ Motivation in Physics in Nyeri County, Kenya

This study aimed at finding out the effects of Experiential Cooperative Concept Mapping ECCM on students’ motivation to learn Physics. Solomon Four Non-equivalent Control Group Design under the quasi- experimental research was used. A stratified random sample of 12 Secondary Schools was drawn from Nyeri County. Four boys’ alone, four girls’ alone and four co-educational schools were randomly assigned to four groups with a total of 513 Form Two students. Students in all the groups were taught the same Physics content of Magnetic Effect of Electric Current. The experimental groups were taught using ECCM approach while the control groups were taught through Regular Teaching Methods (RTM). Two groups were pre-tested prior to the implementation of treatment. After five weeks, all four groups were post-tested using the Student Motivation Questionnaire (SMQ). The instrument was validated and pilot tested before use. The reliability coefficient for SMQ was 0.81.  The instrument was scored and data analyzed using t-test, one-way ANOVA and ANCOVA at a significance level of alpha equal to 0.05.  The results of the study revealed that there was a statistically significant difference between the motivation to learn of students who were taught through ECCM and those taught through RTM. The researchers recommend the used of ECCM in addressing motivation of students towards learning physics. Keywords: Experiential Cooperative Concept Mapping (ECCM), Regular Teaching Methods (RTM), Secondary School students, Physics, Motivation, Nyeri County

The ASOS Surgical Risk Calculator: development and validation of a tool for identifying African surgical patients at risk of severe postoperative complications

Background: The African Surgical Outcomes Study (ASOS) showed that surgical patients in Africa have a mortality twice the global average. Existing risk assessment tools are not valid for use in this population because the pattern of risk for poor outcomes differs from high-income countries. The objective of this study was to derive and validate a simple, preoperative risk stratification tool to identify African surgical patients at risk for in-hospital postoperative mortality and severe complications. Methods: ASOS was a 7-day prospective cohort study of adult patients undergoing surgery in Africa. The ASOS Surgical Risk Calculator was constructed with a multivariable logistic regression model for the outcome of in-hospital mortality and severe postoperative complications. The following preoperative risk factors were entered into the model; age, sex, smoking status, ASA physical status, preoperative chronic comorbid conditions, indication for surgery, urgency, severity, and type of surgery. Results: The model was derived from 8799 patients from 168 African hospitals. The composite outcome of severe postoperative complications and death occurred in 423/8799 (4.8%) patients. The ASOS Surgical Risk Calculator includes the following risk factors: age, ASA physical status, indication for surgery, urgency, severity, and type of surgery. The model showed good discrimination with an area under the receiver operating characteristic curve of 0.805 and good calibration with c-statistic corrected for optimism of 0.784. Conclusions: This simple preoperative risk calculator could be used to identify high-risk surgical patients in African hospitals and facilitate increased postoperative surveillance. © 2018 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.Medical Research Council of South Africa gran

Maternal and neonatal outcomes after caesarean delivery in the African Surgical Outcomes Study: a 7-day prospective observational cohort study.

BACKGROUND: Maternal and neonatal mortality is high in Africa, but few large, prospective studies have been done to investigate the risk factors associated with these poor maternal and neonatal outcomes. METHODS: A 7-day, international, prospective, observational cohort study was done in patients having caesarean delivery in 183 hospitals across 22 countries in Africa. The inclusion criteria were all consecutive patients (aged ≥18 years) admitted to participating centres having elective and non-elective caesarean delivery during the 7-day study cohort period. To ensure a representative sample, each hospital had to provide data for 90% of the eligible patients during the recruitment week. The primary outcome was in-hospital maternal mortality and complications, which were assessed by local investigators. The study was registered on the South African National Health Research Database, number KZ_2015RP7_22, and on ClinicalTrials.gov, number NCT03044899. FINDINGS: Between February, 2016, and May, 2016, 3792 patients were recruited from hospitals across Africa. 3685 were included in the postoperative complications analysis (107 missing data) and 3684 were included in the maternal mortality analysis (108 missing data). These hospitals had a combined number of specialist surgeons, obstetricians, and anaesthetists totalling 0·7 per 100 000 population (IQR 0·2-2·0). Maternal mortality was 20 (0·5%) of 3684 patients (95% CI 0·3-0·8). Complications occurred in 633 (17·4%) of 3636 mothers (16·2-18·6), which were predominantly severe intraoperative and postoperative bleeding (136 [3·8%] of 3612 mothers). Maternal mortality was independently associated with a preoperative presentation of placenta praevia, placental abruption, ruptured uterus, antepartum haemorrhage (odds ratio 4·47 [95% CI 1·46-13·65]), and perioperative severe obstetric haemorrhage (5·87 [1·99-17·34]) or anaesthesia complications (11·47 (1·20-109·20]). Neonatal mortality was 153 (4·4%) of 3506 infants (95% CI 3·7-5·0). INTERPRETATION: Maternal mortality after caesarean delivery in Africa is 50 times higher than that of high-income countries and is driven by peripartum haemorrhage and anaesthesia complications. Neonatal mortality is double the global average. Early identification and appropriate management of mothers at risk of peripartum haemorrhage might improve maternal and neonatal outcomes in Africa. FUNDING: Medical Research Council of South Africa.Medical Research Council of South Africa