We would say that the control group should show a negative or null effect.

Gregor abstained, having a deliberately null effect on the outcome.

The weight of subsequent evidence supports either a null effect, or short-term effects related to increases in mood and arousal, with mixed results published after the initial report in Nature.

Their analyses confirmed that papers reporting null effects of soft drinks or breast-feeding on obesity were cited significantly less often than expected, and, when cited, were interpreted in ways that mislead readers about the underlying finding.

In high-accuracy work, the volume of the article can be measured to mathematically null the effect of buoyancy.

But he did not have to speak, because the null effect did not extend to his mind.

Among women who had interval tubal sterilization, studies have shown a null or positive effect on female sexual interest and pleasure.

He also conducted research on the power of prayer, concluding it had none by its null effects on the longevity of those prayed for.

More to the point, failures to replicate are null effects and can occur for many different reasons.

Sievenpiper JL, Arnason JT, Leiter LA, Vuksan V. Decreasing, null and increasing effects of eight popular types of ginseng on acute postprandial glycemic indices in healthy humans: the role of ginsenosides.