The effort distribution in the testing phase of software development can vary depending on several factors, including the size and complexity of the project, the development methodology being used, and the specific testing activities involved.
While it is challenging to provide an exact percentage that universally applies to all projects, the effort distribution in the testing phase is typically considered significant.
In general, it is common for the testing phase to consume around 25% to 50% of the overall development effort, but this can vary.