The infrequency of femoral head fractures makes comparative studies difficult.
Furthermore, different measurements of personality make studies difficult to compare.
However, the infrequent need for paracentesis in pediatric patients would make design of such studies difficult.
The various classification systems make comparison between studies difficult to interpret.
The methodological variability between research teams makes comparisons between studies difficult or nearly impossible.
Level B. The various classification systems make comparison between studies difficult to interpret.
The absence of a working definition of FRI renders existing studies difficult to evaluate or compare.
These differences in procedure and analysis make comparison of results across studies difficult.
We conclude that experimental design criteria are inconsistently applied making comparisons across studies difficult.
The bias in America for chemotherapeutic treatment has made studies difficult.
There are no standardized models around making comparisons between studies difficult.
