WHETHER it is rendered poetically (“Simplicity is the glory of expression”) or pointedly (“Keep it simple, stupid”) Madison Avenue has embraced the idea of simplicity as a marketing tactic, spurred by growing interest among consumers in products and services they believe will make their lives less complicated or cluttered.

A notable example of the trend is an annual report, known as the Global Brand Simplicity Index, that has been compiled since 2010 by Siegel & Gale, the brand and corporate identity consultancy that styles itself as “the simplicity company.” The 2014 edition, being released on Wednesday, expands the report by adding a list that ranks so-called disrupters: new and newish companies like Ally, GoPro, Nest and Uber that seek to upend traditional marketing methods in categories like banking, retailing and transportation.

Siegel & Gale’s interest in simplicity began with a founder, Alan Siegel, who has long called for corporations and government agencies to simplify the way they communicate with consumers and the public. (Mr. Siegel retired from Siegel & Gale in 2012 and subsequently opened another firm, Siegelvision, where he continues to promote simplicity through efforts like a book, “Simple: Conquering the Crisis of Complexity,” that he wrote with Irene Etzkorn.)

Mr. Siegel, who is chairman emeritus of Siegel & Gale, “raised us on the mother’s milk of simplicity,” said Howard Belk, co-chief executive and chief creative officer of Siegel & Gale, referring to himself and David Srere, co-chief executive and chief strategy officer.