In addition, the effectiveness and safety of long-term use of these agents remain to be determined.

The long-range effectiveness of that approach remains to be demonstrated.

But the effectiveness of such blocks remains to be seen.

The effectiveness of somewhat higher interest rates in slowing growth, however, remains to be seen.

Learnfare has been politically popular around the country, though its effectiveness remains in doubt.

For the time being the effectiveness of such treatments remains based solely on anecdotal evidence.

But its effectiveness in that area remains to be seen.

The effectiveness of all these measures remains to be seen.

The effectiveness of the new release programs, however, remains to be seen.

Still, the long-term effectiveness of the approach remains to be seen.