A fourth-quarter agency survey from media-buying agency Strata found that 53% of agencies report thinking their businesses will grow in 2015 compared to a year ago. Forty-five percent said they plan to hire more staff. About 35% said their clients plan to increase budgets from last year, representing a 50% increase from just two years ago. The study found that TV leads digital, at 44%, as the medium from which most clients will focus, compared -- with 27%, respectively, followed by digital video in third place. Some 41% said that media mix was the biggest concern for ad agencies for the second straight quarter, followed by client attraction at 32%.