The grades of three service stocks are better this week, according to the Portfolio Grader database. Every one of these stocks has an “A” (“strong buy”) or “B” overall (“buy”) rating.

Graham Holdings Co. (GHC) is making headway this week, with the company’s rating improving to an A (“strong buy”) from a B (“buy”) last week. Graham Holdings is a diversified education and media company whose principal operations include educational services, newspaper print and online publishing, television broadcasting and cable television systems. In Portfolio Grader’s specific subcategory of Earnings Momentum, GHC also gets an A. At present, the stock has a dividend yield of 10.2%. For more information, get Portfolio Grader’s complete analysis of GHC stock.

JTH Holding, Inc. Class A (TAX) earns an A this week, jumping up from last week’s grade of B. JTH Holding provides federal and state tax preparation services and related financial products through retail offices and online in the United States and Canada. At $27.58, the stock is above the 50-day moving average of $26.82. For more information, get Portfolio Grader’s complete analysis of TAX stock.

This is a strong week for Cambium Learning Group, Inc. (ABCD). The company’s rating climbs to A from the previous week’s B. Cambium Learning Group provides intervention curricula, educational technologies, professional services, and other research-based education solutions in the United States. Shares of the stock have been changing hands at an unusually rapid pace, twice the rate of the week prior. For more information, get Portfolio Grader’s complete analysis of ABCD stock.

Louis Navellier’s proprietary Portfolio Grader stock ranking system assesses roughly 5,000 companies every week based on a number of fundamental and quantitative measures. Stocks are given a letter grade based on their results — with A being “strong buy,” and F being “strong sell.” Explore the tool here.