Talking of the achievements of the Full Stop campaign at an event organised by the Centre for Charity Effectiveness last month, Marsh said the NSPCC had deliberately set itself ambitious targets that critics dismissed as unrealistic.
"So far we have raised £175m, which we would not have raised unless we had the aspirational goal of raising £250m to start with," said Marsh.
Although the Full Stop campaign has the broad goal of ending all child cruelty, Marsh emphasised that it is important to have milestones along the way.
She added that a key ingredient of a successful campaign is the need to learn from mistakes.
Since Full Stop's launch, the NSPCC has run a number of controversial media campaigns dealing with the issue of child abuse.
One television advert in the style of a cartoon portrayed a child being subjected to violence. The ad was condemned for resorting to shock tactics, but Marsh defended it.
She said: "We needed a big change, so we wanted to shake people up. There's a lot of denial about the problem - we wanted to bring about a cultural change by showing people that child cruelty is unacceptable."
But Stuart Etherington, chief executive of the NCVO, argued that working behind the scenes can be more effective than high-profile campaigns.
"One of the most impressive policy developments has been the introduction of civil partnerships, about which there has been little public campaigning - although I understand Stonewall has had an effective lobbying effort."
This more low-key approach was entirely deliberate, according to Alan Wardle, director of parliamentary affairs at Stonewall.
He explained: "We wanted to bring about a legislative change, so we needed to persuade the people who could make that change - parliamentarians.
"We got Lord Lester to launch a Private Member's Bill that forced the Government to confront the issue."