The overall trend is clear — by many different metrics, Congress is getting worse. But the end of the year has brought a bit of a surprise, via a new analysis from Drew DeSilver of the Pew Research Center. Overall, this Congress has enacted slightly more laws overall than the Congress of 2011-2012.
Of course, not all laws are created equal — some new laws merely name post offices or courthouses. So Pew used what DeSilver calls "deliberately generous" criteria to separate out the least substantive ones. They counted "anything besides building renamings, commemorative-coin issuances and other purely ceremonial laws" as a "substantive" law, and found that this Congress narrowly edged the previous one in these too.
An overall downward trend in both overall and substantive laws that are enacted is clear from this chart. But the years in which the House and Senate are controlled by different parties — most of 2001-2002, and 2011-2014 — were particularly unproductive. So it's possible that the newly-GOP-controlled Senate will be able to pass more laws, though of course, that depends on how many they can get President Obama to sign.