This article is about how the media choose to report economic data, based on who is President. It includes extensive analysis over a 20 year span. The last part makes the case the best:
President Obama also got over 20 percent more positive headlines than our data indicated that similarly situated Republicans would have gotten. This more positive coverage has a real impact on people’s perceptions of the economy. More positive headlines raised people’s perceptions that the economy was getting better. The average difference in positive headlines between Democrats and Republicans produced about a four-percentage point increase in respondents viewing the economy as getting better.
In a close election, that difference can mean a lot.