مطالب

Risk parity is perceived as one of the stock portfolio selection models that have received a lot of attention since the US financial crisis in 2008. The philosophy of this model is to allocate the same amount of portfolio risk between the constituent assets. In the present study, the combined portfolio selection model of relative robust risk parity is introduced, which uses the worst-case scenario approach on the covariance matrix parameter appearing in the robust risk model in portfolio robustness. According to historical data, several scenarios are considered for the covariance matrix. The objective function value of the hybrid model for each portfolio (feasible point) is the worst result (with most volatility) among the set of scenarios.  Finally, the model selects a portfolio for which the worst possible result has the least relative volatility. The research portfolio consists of 8 industries from Tehran Stock Exchange in the period 2011 to 2020. This portfolio has a higher Sharpe ratio than conventional models of mean-variance and weight parity, and is more resilient to market declines than the two models and produces less loss. Therefore, risk-averse investors are advised to use this stock portfolio selection model as a cover to face severe market declines.

With the abrupt emergence and development of the COVID-19 pandemic, face-to-face classes have been replaced with online classes (OCs) on an unprecedented scale in Iran. To improve the quality of OCs, it is quite essential to examine to what extent students are satisfied with them. With this aim, the current mixed-methods study purported to examine university students’ learning satisfaction with OCs at Ayatollah Borujerdi University. For the quantitative part, a total of 509 university students, including males (N=34) and females (N=475) filled out a modified version of the Satisfaction with Online Classes Survey (SWOCS) developed and validated by Bolliger and Martindale (2004). For the qualitative part, a sample of 20 students, consisting of males (N=9) and females (N=11) completed a reflective written statement disclosing their perceptions of OCs. Findings evidenced that the participants are moderately satisfied with OCs. In addition, the results of Friedman test documented that all the sub-factors of SWOCS played an important role in the participants’ learning satisfaction with OCs. Complementary with the quantitative findings, the qualitative results yielded five overarching themes: “instructors are a critical factor for students’ learning satisfaction’, ‘familiarity with technology affects students’ learning satisfaction’, ‘course set-up shapes students’ learning satisfaction’, ‘interactions with others are vital’, and ‘students’ learning satisfaction is closely correlated with outcomes’ Finally, a range of implications is proposed for different stakeholders.