"reasonable indication" is correct and usable in written English.
You can use it to refer to an indication that a situation or a certain point of view has some kind of reasonable backing or supporting evidence. For example, "The fact that he was seen in the area gives a reasonable indication that he was involved in the robbery."
That's a reasonable indication that the peer-to-peer pioneers have started something significant.
The performance of the world's biggest advertising company is a reasonable indication of whether its clients are prepared to spend.
So the dates are a bit off, although they are believed to be a reasonable indication of what theatres would have been like half a century earlier.
In chess, simply adding up the value of each piece left on the board gives a reasonable indication of the strength of a player's position.
Many investigators agree that 2 mm of articular displacement is a reasonable indication for open reduction and internal fixation of Mason type II fractures of the radial head.
The United States International Trade Commission, by a vote of 6 to 0, said there was a reasonable indication that low-priced imports of various forms of Carbazole Violet Pigment 23 were harming domestic producers.
Using modern weather station data, these indices have generally been shown to provide reasonable indications of dune activity potential.
"We got reasonable indications that this was O.K.," Sergey Brin, a Google founder and its president of technology, said.
"There have been reasonable indications that the economy is recovering and you'd expect money flow to go along with that," Mr. Hayes said.
The disclosure also raised troubling questions about whether the city was violating a federal court order that bars it from retaining information gleaned from investigations of political activity unless there are reasonable indications of potential wrongdoing.
The restrictions had two purposes: to prevent the department from unfairly targeting entire political or religious groups, and to make sure that records were kept only when the police found "reasonable indications" of potential law breaking, not as an intrusion into the private affairs of innocent citizens.
