Questions are being raised about the fairness of Nassau County's property tax assessment system.  

Newsday investigative reporter Matt Clark looked at the county's so-called "Carry Forward" initiative. Clark's report says clients of the two biggest politically connected tax appeal firms received reductions of 11 to 18 percent in 2012. 

Others who grieved their taxes but didn't use those firms only got a negotiated reduction of 9 percent.

"Former County Executive Mangano wanted to avoid having the county have to pay property tax refunds," says Clark. "County Executive Mangano's reforms or overhauls of the assessment system was intended to address that problem, but in the process it produced the most unfair and inaccurate assessments we've seen since before 2000."