Most mergers end up as disasters. Studies shows that as many as 75 per cent fail to deliver value for shareholders.

So why are so many mergers like groundhog Day? Why the same mistakes over and over again?

Carter Utzig from the accounting and consulting firm Dixon Hughes compares the merger to marriage in this interesting piece.

Nothing new in that, but it does make the point that like any successful couple, the merger parties need to spend more time assuring that they will understand all aspects of the relationship in order to build a stronger entity.

Unfortunately, companies don't do this because most of the due diligence focuses on the accounting-related issues, and implementation executed by the financially-oriented managers. The "people" issue is usually ignored.

Utzig writes: "Virtually every business will reach a point when it considers a transaction to merge or acquire. Transaction? Isn't it more like a marriage when you combine two companies comprised of different individuals with different cultures and capabilities?

"Think about the 'dating' process before a merger or acquisition - the focus is around 'getting the deal done.' Such narrow focus typically results in only enough analysis to support the deal's pricing and financing. And sometimes in the passion of the deal, details are overlooked."

Details such as how to retain value (by not losing customers, key employees and focus), how to realise and enhance value, designing the nitty-gritty of how all aspects of the organisation, from practices and structure to people and technology, will work together, determining the right strategy, crafting a new single culture more real than what's on paper, and planning for evolution than doing it with a big bang. In other words, you need to treat it as the beginning of a process rather than the end game.

Or as Utzig puts it, take the time to get to know your potential spouse and decide on money, children, religion, whose furniture survives and which gets turfed out.

Professors Jeffrey Pfeffer and Robert Sutton dissect the problem with mergers in their book Hard Facts, Dangerous Half-Truths And Total Nonsense .

Sutton looks at what needs to be done on his blog.

He suggests companies can learn a lot from the way Cisco executes a merger. That includes seeing the merger as the acquisition of people and focusing on the development of a career path within Cisco for each person in each company they acquire.