"How is 88/148 score on the usmle cd 2011 correlated to the actual step 1 score. Is it in the passing range or should i be worried..."
The Questions on the USMLE Website and USMLE CD are designed to familiarize the student with the FRED software and question formats to be expected on the examination. It is not necessarily a reflection of the difficulty of the actual examination, nor meant to be an estimator of your progress or ability to pass the actual examination. We do not know how to translate the score and am baffled as to why a score is provided with no translation except to emphasize that the questions are not to be used as predictions.
Several students have done fine on this sample test, but have difficulty on the actual exam. In past years, it has proven to be too easy a practice exam to be representative of a student’s actual performance on the real exam. We would recommend sticking with patterns in question sets that have proven themselves over the years. Unless you are scoring above 70% consistently (on the last 20-25 sets of 40 questions on USMLE World or Kaplan Question Banks) and/or are scoring in 195 or above on 2 or more of the NBME self assessments for Step 1, it would not be wise to take your exam at this time. It would be best to take some time to continue with preparation.