Murphy uses a three-year chart of the XLV alongside the ratio of the XLV to the SP 500 Index, providing a measure of health care's relative strength. When it rises, the implication is bearish for stocks. Their relative strength ratio rises when the market is weak and falls when the market is strong, ... The fact that it's been rising for most of 2005 is a sign that money is moving into more defensive sectors in an aging bull market--another reason why health care is an attractive choice right now.