The ISM (formerly NAPM) survey data correlate well with overall US economic activity, though not 100% at the month-to-month level. They pretty much get the major and the minor cycles. My judgement of last month's data (smoothed by my extreme adjustment program using the NBER's method) is that the slowdown apparent in recent months has come to an end. Tonight (early morning US Friday) we'll get the employment and unemployment data for August, and we'll see whether that's evident in these numbers too.
Disclaimer. After nearly 40 years managing money for some of the largest life offices and investment managers in the world, I think I have something to offer. These days I'm retired, and I can't by law give you advice. While I do make mistakes, I try hard to do my analysis thoroughly, and to make sure my data are correct (old habits die hard!) Also, don't ask me why I called it "Volewica". It's too late, now.
BTW, clicking on most charts will produce the original-sized, i.e., bigger version.