Hard to say since they use what they call 'weighting' to adjust for known biases. If they listed their questions it would be easier to know. The random phone sample tells us nothing of the demographics. How many Dems, Repub, independents and were in the sample? It's probably about a mid 40's approval rating.
Some poll info.....
http://people-press.org/reports/questionnaires/269.pdf
Didn't follow the link did you? In the Pew study, 30% were Republicans, 33% were Democrats, 31% were Independents, 3% were no preference, and 3% didnt know.