There is some confirmation bias at work anyway. A group might not publish a report that indicates that a sasquatch attacked or abducted somebody, or a sighting that was also associated with a UFO sighting if those things don't fit the group narrative. We are dealing with an amateur army of enthusiasts to even get these reports.
I don't cull reports. If they get published by the organization (for the most part) they get an entry. I might skip those where I can't narrow down a reasonable location.
If I rated an entry "low" there was something I didn't like about it, but it's in the SSR anyway. My opinion is not the only one that counts.
There are a few that are "late 70's", where they can't even give a year, that still may have an entry if the location is reasonable.
If you want "better" reports, you might consider skipping the ones from the early days of the BFRO, where many were published without investigator follow up. These are probably not easy to exclude at the moment. I would enter "unknown" for investigator, and other people entered "N/A". In hindsight, I should have separated the ones with no investigator comment at all vs. the ones with comment from an unnamed investigator. There are plenty of both.
If I was interested in where they were season by season. I'd limit the search to witness activity "driving", which are as Bobby says, chance encounters, There are a few spring - fall reports that happen in areas that have closed roads in the winter. They may be there but people that could encounter them are not.
A thought I had about seasonal reports is that the SSR entries are based on season dates, not months. December 1-19 is "Fall" but when I'm shoveling "Fall Snow" it sure feels like winter.
It might be interesting to do monthly searches "for a different perspective".
Dec, Jan, Feb = Winter
Mar, Apr, May = Spring
Jun, Jul, Aug = Summer
Oct, Nov, Dec - Fall
I'm working a little bit on the Oregon Bigfoot database. These entries are a bit frustrating in that practically NONE of them get investigator follow up. They consistently score low because of that, but I think they are valuable anyway.
Edit to add: There may be a lot of potential sasquatch activity in areas that don't show up in the databases, simply because the group would like to keep these locations secret. I have "heard" of many encounters in Iowa, Wisconsin, and Minnesota that are not published.This is from people who get out often for outings to see what they can see. On Sunday, I was dropping off a recorder in some local woods and heard a tree crash when I turned to leave. A few minutes later I recorded two daytime wood knocks. That might be enough to get a class B report, but I won't file one. A BFRO investigator was with me at the time. (tree crash audio Link - I was doing side by side mic testing - I have built a microphone with a built in low pass filter to quiet the bugs)