I don't know.
Ontario's salary disclosure legislation, which requires that all salaries over $100,000 per year be made publicly available, was introduced by the Progressive Conservative government of Premier Mike Harris. That government had a somewhat unenthusiastic attitude towards MUSH (municipalities, universities, schools and hospitals) and the public service. The aim of the legislation was, presumably, to build support for policies to restrict and limit public sector salaries, and put downwards pressure on salary growth.
Yet no one scrutinizes Ontario's public sector salary disclosure document more closely than public sector employees themselves. We look for salary anomalies, something that will help our case before the salary rationalization committee. We look to see if our salaries are competitive with those of people in other institutions, and if they're not, we complain. To the extent that salary disclosure encourages levelling up, it would be expected to increase public sector salary growth.
In other contexts, such as CEO pay, there is a perception that disclosure of executive compensation has led to salary growth through the Lake Woebegone effect: every CEO wants a better-than-average pay cheque. (I buy that story.) However, as this article suggests, it is not easy to find clear-cut evidence that disclosure per se is behind the explosion of executive salaries.
Likewise, it not easy to find a rigorous estimate of the impacts of the Ontario salary disclosure legislation on public sector salaries, although this paper suggests that salary disclosure has not dampened salary growth.
I did find one paper that suggests that university employees who discover, through salary disclosure, that they earn less than their colleagues respond by getting angry and/or working less. I believe it. (That's the thing about academic life - one can't do much about ones salary, but one can do a lot to change ones wage rate).
But other than making some people feel underpaid and resentful, has salary disclosure had much impact? I just don't know.