By now everyone knows the fate of their IOS or DEB preproposals. The decline rate is high, even at this stage, so don't get all bummed out if your preproposal didn't get picked up. The most critical part of learning from the reviews is to separate the science from you as a researcher. This isn't personal.
No matter what the outcome of your preproposal, I suggest contacting your PO to set up a time to talk. Set up a time by email and include your proposal number so they can quickly find the information they need. The first thing I want to find out about a proposal relates to how it fell in the context of the panel. When you first open the reviews window in FastLane most people dive right into the panel summary and individual reviews. But an important piece of information lays below those links: The Context Statement. Below are the percentile break downs from two of my recent preproposals.
The panel placed 12% of the pre-proposals in the "High Quality" category, 52% in the "Medium Quality" category, 31% in the "Low Quality" category, and 5% in the "Not Competitive" category.
High Priority for Invite (21%), Low Priority for Invite (7%), Not Invite (72%)
As you can see, there are substantial differences that extend beyond the terminology. In the first example, the "Not Competative" category is a pretty clear signal that you should probably scrap that proposal. It was universally despised, time to move on. "Low Quality" is less harsh, but you're not even cracking the top 60% and it's probably worth considering different ideas. Medium is where it gets interesting and if your proposal lands in this pool, you need to figure out if it was closer to competitive (some mediums were invited because only 12% made "High Quality") or hanging around closer to the riff-raff in LQ. Your PO can shed some light on this and give you more information than "You were in the middle 50%".
In the second case, the "Not Invite" category is a pretty inclusive bunch. Again, were you near the top of this group but might not have justified your approach, or are you better off coming up with a new approach? Some of this will be evident from the reviews and summary, but the POs can hopefully point you in the right direction for that particular panel.
You may also want to inquire whether a different panel might be better suited to review your proposal. NSF does tend to move proposals if they think there is a better panel fit, but sometimes the reviews expose this more than initially thought.
Finally, it's critical to have a good conversation about what the PO thinks will make your proposal a fundable one (Generally. They're not going to plan experiments for you). This is true whether your preproposal was invited or not and this is where the value of the conversation lies. The panel summary will certainly provide you with important information, but the POs have the benefit of the umbrella view. They know the typical range of their panels, who are the panelists who are coming back to do the full proposal round and what their particular bugaboo was. If you explain what you see from the reviews and inquire whether there are other things you should be taking note of, the PO might point out something you're not seeing because you happen to be overly-focused elsewhere.
Also, the panel rankings are only recommendations, so there may be things the PO believes are important that the panel summary does not convey. Perhaps important comments were made in discussion that did not make the summary. Sometimes those things are written under a certain amount of "duress". However, I have had the most success with proposals when I have asked the PO what they think it will take to make the proposal competitive and then tried to focus on those points. Sometimes it's all laid out in the panel summary and sometimes a phone conversation can really help you target certain things. Questions like "Would the proposal be more competitive if we were able to address xxxx?" can help you hammer out a plan for resubmission. Maybe you need data or maybe you just need to better justify an approach.
Even if you learn nothing new from your conversation with your PO, it never hurts to get on the horn and see what they have to say. Remember that they didn't write the reviews or the summary statements, so calling them when you are upset about either of those is simply counter-productive. Let the reviews breathe, then figure out how to make an improvement and get funded.