The phrase "a solid indication for" is correct and usable in written English.
It can be used when discussing evidence or signs that support a particular conclusion or action.
Example: "The recent data provides a solid indication for the need to revise our marketing strategy."
Alternatives: "a strong sign of" or "a clear indication of".
We generally don't consider products at the "idea" stage that are not brought by successful repeaters or unless they have a solid indication of demand (from extensive customer discovery, for instance).
The category of total appeal is a solid indication of how attractive a candidate is as a presidential contender.
Even the staggeringly slow motor traffic is a solid indication of the constant buzz that comes with a strong economy and heavy tourism.
In the hearing on Wednesday, Pauffley said the "expression of views [by Butler from the dock], albeit in the heat of the moment immediately after the verdict, gives a solid indication this criminal process is likely to extend to the making of an application for permission to appeal or a submission should be made that this conviction should be overturned.
Producers of the show were expecting close to $1 million in ticket sales by day's end, a solid indication that an Italian-language opera can succeed on Broadway.
Although our analysis provides a strong indication for a positive feedback in Z. marina ecosystems, it does not offer solid proof.
Nevertheless it still represents a strong indication for a decision maker, suggesting that it is 'safer' including public research in a future program, since it is the easiest way to keep a solid relationship network within the productive system.
The report gives a very solid indication of just how much the crowdfunding industry has changed over the last few years (and will continue to change).
The only solid indication of a mature ontogenetic stage in both groups is the shaping of the morphological characteristics.
