Specific, credible numbers do persuasive work that adjectives simply can't — they give a skeptical reader something concrete to evaluate rather than take on faith.
Use Precise Figures Instead of Round Ones
An oddly specific number, like "37% faster" rather than "much faster," reads as more researched and more believable.
Cite Where the Number Comes From
Attaching a source or a brief explanation of how a statistic was measured strengthens its credibility considerably.
Don't Overload the Letter With Numbers
A handful of well-placed, meaningful statistics carries more weight than a letter so dense with figures that none of them stand out.
Next step: Use the Sales Letter Writer to work specific, credible numbers into the claims throughout your draft.