But there isn't a successful model for mass change.
But it's become clear that there is no one successful model for dairy farming.
They may yet defy cynics and become a successful model for single-payer care.
"Our readers have embraced our digital strategy, which has provided a successful model for the industry," he said.
What has been a wildly successful model for consumer Internet start-ups in Silicon Valley turns out to be an extremely good model for learning in a wide variety of fields and disciplines.
Even television has a successful model for charging more for shows that a smallish group of people feel passionately about, in the form of premium subscription channels like HBO.
Strong property rights and market incentives have provided a successful model for rhino conservation, despite the negative impact of command-and-control approaches that rely on regulations and bans that restrict wildlife use.
The Internet Watch Foundation (IWF) has a successful model for dealing with child abuse imagery if measured by the fact that, since its launch in December 1996, it has removed more than 100,000 images of child abuse from the web, in response to reports made through its hotline.
The report says the IFC has acted irresponsibly, "both in terms of its role as a transaction adviser to the government of Lesotho and in its marketing of the Lesotho health PPP as a successful model for other low-income countries to replicate".
By 'mapping', and by avoiding drawing up "false narratives" about conflict and appropriations regarding men in the context of rape – through rethinking how their literature is written and how they understand war – NGOs can lay the foundations for a successful model for dealing with male rape.
At one level, it was not nearly so crazy as it looked: a slave insurrection had succeeded in Haiti almost within living memory, and Brown's plan remained a successful model for Latin-American guerrillas into our own time, right down to the mélange of outside agitators and local agrarian rebels.
