...from January 26, 2009
This week Senate Minority Leader Mitch McConnell suggested suspending the Social Security payroll tax for a period of time, as a stimulus measure. A payroll tax holiday, however, would both be costly — a two-month suspension
could cost about $120 billion, for example— and likely relatively ineffective as a stimulus measure. Public resources would be better spent on stimulus measures with a higher “bang for the buck,” such as the Making Work Pay tax
cut that President-elect Obama has proposed.
Biggest Tax Benefits from Payroll Tax Holiday Would Go to Workers Least Likely to Spend Them
Economic stimulus measures aim to encourage an immediate increase in aggregate demand by boosting consumer spending. The most efficient way to boost consumer spending is to put money into the hands of people who will
spend it quickly rather than save it; tax cuts focused on moderate- and low-income households are more effective as stimulus than tax cuts that are larger for people with higher incomes, because people at low-income levels spend
a larger share of tax cuts they receive than people at higher income levels do.
http://www.cbpp.org/cms/index.cfm?fa=view&id=2264