Over this past year, analysts felt pressure to keep their assessments positive. In order to report bad news, current and former officials said, the analysts were required to cite multiple sources. Reporting positive news required fewer hurdles. Senior officials sent emails cautioning against using pessimistic phrases that they said were more likely to get attention, according to one former official. In some instances, officials said, conclusions were completely changed.The tool is a hammer, and that hammer had better be working well.