UBS has upgraded FTSE 250 recruitment firm Hays from neutral to buy, saying that while short- and medium-term macro concerns are rising, the group still has good growth prospects in the long-term.The Swiss broker notes that while data points across the sector have been robust in the second quarter, "visibility is also limited and recent macro/market volatility clouds the picture". Furthermore, it thinks that the outlook in the UK remains poor with no growth recovery and highly-depressed profitability.However, "we continue to believe that Hays is a good business with well-established and strong franchises in professional staffing, and a meaningful and fast-growing international presence (62% of net fees in 1H11 came from outside the UK)," the Swiss broker said.The target price is left at 105p.At 10.29am on Thursday, shares were trading 3.3% higher at 75p.BC