In 2012, Potash Corporation of Saskatchewan reported a profit margin of 20.2% using net income in the numerator. Had the profit margin been based on total comprehensive income, instead of net income, the revised profit margin would have decreased to 12.0%. In 2014, its profit margin was 21.6% using net income and 17.7% using total comprehensive income.
(a) Has Potash's profitability improved or deteriorated in 2015?
(b) Which profit margin-without other comprehensive income or with other comprehensive income-is the most appropriate ratio to use in this particular case for analysis purposes? Explain.