Yes, there is definitely a correlation, in the sense that when you see women join one of these groups, initially the typical member is very shy and reluctant to speak up in the group meetings, especially if there is a foreigner in attendance. It's quite remarkable that a few meetings later, or after a month or two of their participation, you can see a marked difference in their self-confidence and willingness to speak up, and in other, softer manifestations of empowerment.
Their actual decision-making power within their household and within their community takes longer and is more problematic. It depends very much on the microfinance institution and the effort it puts into training these groups to help them become self-managed, and for the women themselves to control what's going on—that's what's most empowering. But just the act of taking a loan and successfully repaying it can be very empowering, at least in some dimensions.