Each weekday, TheStreet.com Ratings updates its ratings on the stocks it covers. The proprietary ratings model projects a stock's total return potential over a 12-month period, including both price appreciation and dividends. Buy, hold or sell ratings designate how the Ratings group expects these stocks to perform against a general benchmark of the equities market and interest rates.While the ratings model is quantitative, it uses both subjective and objective elements. For instance, subjective elements include expected equities market returns, future interest rates, implied industry outlook and company earnings forecasts. Objective elements include volatility of past operating revenue, financial strength and company cash flows. Electrical parts manufacturer Deswell Industries ( DSWL) has been downgraded to a hold from a buy. TheStreet.com Ratings believes the company's 17.2% gross profit margin is rather low. It has decreased from the same quarter of the previous year. Along with this, the net profit margin of 5.1% is lower than many of Deswell's peers. The company's 10.9% return on equity trails the industry average of 19.1%. DSWL had been rated a buy since February 2007. Elbit Medical Imaging ( EMITF) has been upgraded to a buy from a hold. The Israeli company develops ultrasound equipment that uses magnetic resonance imaging. However, EMITF is also involved in other businesses including real estate development, women's fashion and venture-capital investments. The company's strengths can be seen in multiple areas, such as its robust revenue growth, largely solid financial position with reasonable debt levels by most measures, notable return on equity and solid stock price performance. Shares of Elbit are up 117.4% in the past year. EMITF had been rated a hold since July 2005.