Hi, quoting directly from the Whitepaper:

The business’s resulting trust rank is a composite number calculated from a weighted sum—the weight being the trust rank of the evaluator, of quantitative evaluations ranging from 1 to 10 and their financial indicators.

The reputational component dissolves over time to ensure relevancy.

This effectively means that the evaluations given from businesses with a greater trust rank will be of bigger importance and the reputational component of the trust rank dissolves over time in a linear manner to ensure that the most weighted evaluations are the most recent and therefore the most relevant too.