Mistakes are easily made, especially with abstract data.
Asked to communicate figures from a newly completed Carbon Management Plan, we found they didn't add up. By careful checking, we found errors that had to be corrected before we could create the images. A few months later we presented, to a very experienced client, a picture of his organisation’s emissions. We were surprised at his response: “That can’t be right!” With quantities shown visually for the first time, he instantly saw that something was wrong and eventually discovered that his data was incomplete. Neither of these clients had asked us to check their figures but in the end our work saved costs and the potential for embarrassment.
Visuals can sometimes bring new insights - even to those most familiar with the figures; and the integrity of communications can be aided by a fresh pair of eyes.