"The club under Mr Duffen spent money it didn't have," added Pearson. "The prospect of relegation should not need to be the doomsday scenario that everyone currently discusses and worries about.
"The financial planning just needed a bit of basic strategy and common sense applying to it back in summer 2008 and even more so when the team survived on the last day of the season in 2009.
"In my personal opinion the decisions made by Mr Duffen at that point were extremely short-sighted."
Duffen issued a statement saying Hull had "one of the lowest squad wage bills in the Premier League and amongst the lowest levels of debt".
He added: "Hull City Football Club have been on an amazing journey over the past four years. The Tigers have travelled from the brink of Championship relegation to Premier League promotion via their first ever Wembley appearance.
"The successes were not achieved through financial muscle but through partnership, ambition, team spirit, collective positive attitude and a stubborn refusal to fail.
Duffen spent just over two years in charge of the Tigers
"I firmly believe that if those qualities remain at the club then Hull City have every chance of playing a third season in the Premier League and I wish them well."
Duffen took over from Pearson in June 2007 and led Hull into the top flight but he resigned in October 2009 with Pearson subsequently resuming his role at the club.
In January, Pearson claimed insufficient care had been taken over transfers and deals and launched legal proceedings against Duffen.
Duffen denied all the allegations against him at a preliminary hearing at the High Court and the two parties eventually settled out of court.
Hull are embroiled in a relegation battle and speaking to supporters through the match programme Pearson explained why Premier League survival was so important.
He wrote: "The problems which were apparent throughout 2009 should have been at the forefront of the summer transfer and business dealings. Instead, the wage bill was increased even further.
"The safety valve of pragmatic realism was cut off.
"This is not ambition or 'giving it a go' or 'living the dream', it is, in my personal view, poor business sense.
"Just under £6m spent on agents' fees in two years and the deal breakdown and size of agent payments is abhorrent. A wage bill of just under £40m when the club turnover is £50m in the Premier League.
"These figures, added to the significant transfer fees owed, clearly show that the maths don't add up."
At the time of Duffen's departure from Hull, a formal statement said the club wished "to express its gratitude to Paul for his outstanding contribution as chairman during a period of unprecedented success for Hull City AFC".
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