Thermal resistance of new package.

Recently Altera said:

"Altera is transitoning their Power Quad Flat Pack (RQFP) package from the PowerQuad® 2 (PQ2) to the PowerQuad® 4 (PQ4) package. Altera is implementing this package change to better support long-term demand for the affected products. The PQ2 package design is being discontinued and conversion to the PQ4 package is essential for continued support.

Thermal resistance (Theta ja) for the PQ4 package design is approximately 1.5°C to 2.0°C / watt higher than the existing design."

What is the actual thermal resistance?