The title says "INCREASES conversion by 10%"…but the data simply reports a correlation that "reviewed products convert 10% higher than non-reviewed products".

Here's the text of the case study…

"Reviewed products convert 10% higher

Upon analysing conversion for products that have been reviewed versus those that have not, Argos found that reviewed products have a 10% higher conversion rate than those without reviews.

Argos came to this conclusion by comparing conversion rates for products with reviews to the overall site average. At the time of the analysis, there were 22,200 products reviewed at http://www.argos.co.uk."

What was the conversion rate of those products before reviews were introduced?

Thanks!

The title says "INCREASES conversion by 10%"…but the data simply reports a correlation that "reviewed products convert 10% higher than non-reviewed products".

Here's the text of the case study…

"Reviewed products convert 10% higher

Upon analysing conversion for products that have been reviewed versus those that have not, Argos found that reviewed products have a 10% higher conversion rate than those without reviews.

Argos came to this conclusion by comparing conversion rates for products with reviews to the overall site average. At the time of the analysis, there were 22,200 products reviewed at http://www.argos.co.uk."

What was the conversion rate of those products before reviews were introduced?

Thanks!