While accepting the Ashes result was "disappointing", Harrison believes that progress made elsewhere showed the ECB was doing good work. As a result, he said there would be no "knee-jerk reactions" to England's defeat and suggested the positions of the coaching staff were quite safe.
In particular, Harrison was encouraged by attendance figures, the success of the women's team at the World Cup, the launch of the All Stars Cricket scheme and changes to the way the ECB is run.
And while it seems doubtful many England supporters will be consoling themselves with the thought that the governance structure of the game has been altered - referred to by Harrison as "an exciting moment as it means the quality of decisions we make will be in the context of the future of the whole game" - the improved performance of the white-ball sides might provide more realistic grounds for encouragement.
"The health of the game is more than just Ashes series overseas," Harrison said. "We've had record-breaking attendances in domestic and international cricket, changed our governance structure, hosted two global events, won the women's World Cup and launched a participation initiative for kids. We've had a successful entry into the broadcast rights market out of which we have secured the financial future of the game until 2024.
"It's a shame this series hasn't gone our way but there's more to play for over the course of the winter. It's also important to remember that in every one of the three games England have been in a position where things could have worked out differently. We just haven't managed to turn the screw in those moments. But we've remained pretty competitive even in Australian conditions.
"We have a plan and we're making progress on that plan. We're in the middle of an Ashes series where England have been very competitive for large parts. What it has shown is that Test cricket is the ultimate form of the game, where those marginal periods of play can turn a game and we haven't been able to do it.
"We are in a process of delivering cricket across three formats. They're making huge strides across the white-ball game, up to a place where we're winning 70% or so of our white-ball matches - the ODI side in particular - and the T20 side is making good progress.
"In Tests we're finding it very difficult to win overseas. We did win a series in South Africa, which is a significant achievement, but we've found it difficult in Dubai, India and here. We've got to take a look at that. There are the moments you understand the progress that's been made and it's very difficult to look at it through the mirror of three matches over the course of a difficult Ashes series."
Harrison did concede that the ECB had been "striving to find the answer" to England's apparent deficit of pace bowling but expressed his belief in the performance centre at Loughborough. Instead, he felt there should be an emphasis on providing more sympathetic pitches for pace bowlers but insisted "this isn't an alarm-bell situation".
"We've a fast bowling programme at Loughborough, which offers excellent results for the guys who go through it," Harrison said. "The work we're doing at Loughborough is there. The talent is there. You've seen George Garton, Mark Foottitt and Mark Wood. They're all at that level. But for one reason for another, they're not coming through. Whether due to injury or consistency. But this isn't an alarm-bell situation.
"These are the situations you can find yourselves in overseas. Sometimes you require different skill sets to the ones you can acquire in your own conditions. We have to look at that and wicket structures. There are questions about whether our wickets reward extra pace and how we can arrive in place with the right firepower to compete.
"We have to be careful not to overreact half way through an Ashes series. We can all understand there's some frustration and we haven't been able to close those matches out. Now is not the moment to be overreacting. There will be no review. This is not the moment for knee-jerk reactions or rash decisions about what we do from here in respect of performance."