Recent study results have been negative, but its effectiveness may vary depending on the preparation.

All of these techniques are variable, and their effectiveness varies with each individual.

The effectiveness of all these procedures varies greatly and depends on individual circumstances.

However, the effectiveness of the tool will vary from image to image.

Although 47 states regulate these schools in some fashion, effectiveness of regulation varies.

The effectiveness of a drill bit varies by formation type.

Health care experts say such agencies' effectiveness, however, varies from state to state.

Though important at times, their effectiveness varies with circumstances.

The effectiveness of these staff processes has varied with the nominee.

Of course, the effectiveness of these techniques varies with the person.