21.   Economists warn, however, that international investment data are too imprecise to draw firm conclusions.

22.   Experts on head injuries discussed the potential risks of heading, but reached no firm conclusions.

23.   Firm conclusions are hard to come by, and some of the authors disagree with the hypotheses suggested by others.

24.   However, Sherry acknowledged that current data is insufficient to draw firm conclusions.

25.   However, some warned against drawing firm conclusions, because specialists in the study may have had somewhat sicker patients.

26.   In most cases, the authors stop short of drawing firm conclusions.

27.   It is perilous, of course, to reach firm conclusions until the house is full and final adjustments have been made.

28.   It is sympathetic but questioning, and fittingly for a picture painted in shades of gray, draws no firm conclusions.

29.   Juanakar said no firm conclusions have been reached as yet.

30.   Other scientists note, however, that tests against a placebo are needed before any firm conclusions can be drawn.