"similar difficulty" is correct and usable in written English.
You can use it to compare something that is of a similar level of difficulty. For example, "I have experienced similar difficulty with this problem before."
McDonough had a similar difficulty: "We advertised for a head of maths and struggled to recruit.
The Blacks had a similar difficulty selling a fruit with a name that no one can pronounce.
Unlike other periods in the past of similar difficulty, it looks as if Israelis no longer have any hope.
For example, "The Red Badge of Courage" and "The Call of the Wild" are novels of similar difficulty but appeal to different students.
For an international test to work, all students have to answer the same questions, or at least questions of similar difficulty.
If a committee of Nobel Prize winners set out to apologize for the sins of science, they would face a similar difficulty, although on a more mundane level.
It seems to be working: revenues this year will be around $60m.Decode faced a similar difficulty in bringing its new genetic test for type II diabetes to market.
If it is replied that the concept of red and others like it are acquired when we are taught the word red in childhood, a similar difficulty arises.
Chrysler, the smallest of the Detroit companies, is in similar difficulty, and asked Congress for a $7 billion loan before the end of December to ward off a potential bankruptcy.
By F. J. Crehan and Russell Maloney The New Yorker, March 22 , 1941P. 9 Our recent item about the verbal barrier in the way of an amalgamation of Poor's Publishing Company with Standard Stastics has reminded one of our readers of a similar difficulty encountered by a man who does research in the field of aeronautical engineering.
"The problem for Obama is that he will be limiting himself in the expertise he can tap," said Martha Kumar, a Towson University professor who studies presidential transitions, noting that President Bill Clinton faced a similar difficulty with less sweeping rules.
