Foundry 測試 1,398 條短片的 13 項變數，發現 Instagram 重複發布與低觀看數關聯最強

Disclosure: I'm on the team that builds Foundry, the tool these posts went out through. The numbers are from our own accounts; the link is at the bottom.

We post short clips of debates to Instagram, TikTok and YouTube Shorts from our own iPhones. Between Aug 31 and Oct 12 that was 1,398 posts with a view count we could read. By early October our Instagram had a problem: more and more posts were stopping at 10 views or fewer, and a few were stopping at zero.

The usual suspects are posting time, hashtags, account age, video length, captions. We tested all of those and a few more, and most of them did almost nothing. One variable stood far above the rest.

How we measured

For each post we kept the platform, the account, the hour, the clip, the source video and its view count. Two outcomes:

• a zero: 10 views or fewer
• a hit: 1,000 views or more

Then 13 variables: posting time, spacing from the account's last post, account age, first frame (letterboxed or full frame), first-second loudness, length, caption template, hashtag count, whether the upload was the original file or a re-encode, where the clip came from, how many accounts share the phone, and two about repeats.

Comparing raw numbers across weeks lies to you, because the weeks were different (our content mix changed a lot). So every comparison is made inside the same week and combined with a Mantel-Haenszel ratio: how much more likely is a zero (or a hit) in group A than group B, holding the week fixed.

What didn't matter much

• Hashtag count: a ratio of 1.0. Nothing.
• Posting time: Instagram medians for the four time blocks sat between 147 and 181 views.
• Caption template, length, first-second loudness, spacing between posts, where the clip came from, account age: ratios between 1.3 and 1.8, next to 4 to 5 for the repeat.
• How many accounts share a phone: it ran the wrong way for a fix. Instagram accounts sharing a phone with two or more others hit 1,000 views more often, not less.

If you have been tuning posting times, this was the least useful lever in our data.

The one real second-order effect was the first frame. On Instagram, clips that opened letterboxed (black bars above and below) stopped at 10 views or fewer 26% of the time, against 10% for clips that opened full frame. Inside the same weeks, full frame roughly halved the chance of a zero. Worth fixing, but it was not the main story.

The one that mattered: the same debate, posted again on the same platform

A "repeat" here means the same source debate going out again on the same platform, even as a different cut or with a different caption, on the same or a different account.

Instagram, by how many times that debate had already gone out there:

A first post zeroed 3% of the time. A second one, 20%. A third or later post on Instagram hit 1,000 views zero times out of 205. And of the 101 Instagram zeros since Sept 28, 92% were repeats.

Waiting doesn't fix it. A debate going out again on Instagram after 14 days or more still zeroed 29% of the time, against 3% for a first post. Whatever Instagram is matching on, it remembers for longer than two weeks.

YouTube is the exception

On YouTube Shorts, posts going out a 3rd to 5th time still hit 1,000 views half the time (12 of 24). Our YouTube numbers are better across the board (median 666 views against 165 on Instagram), so a rule that holds on one platform can be the wrong rule on another. We now cap repeats on Instagram only and leave YouTube alone.

Why it crept up on us

The repeat wasn't a choice. It was supply. In the week of Aug 31, 84% of our Instagram posts were debates Instagram had never seen. By the week of Oct 5 it was 25%. The posting side kept filling every slot on time, and when there was nothing new to fill them with, it reached for clips that had already gone out. Every individual post looked fine. The schedule looked full. The reach quietly fell.

That's the trap with any automated posting setup: a scheduler optimizes for "a post went out", and nothing in that metric tells you the post was a duplicate the platform has already judged.

What we changed

1. Fresh first, on every platform. When choosing what fills a slot, a debate the platform has never seen ranks ahead of everything else, always.
2. Instagram gets at most two posts of any debate. A third one is held instead of posted, with the reason written down ("repeat clip"), so an empty slot shows up as an empty slot instead of a quiet zero.
3. The fix for reach is new source material, not settings. No posting-time or hashtag change was going to move this. More fresh debates will.

What we're still watching

The biggest raw ratio in the whole table was the upload file: the original file vs a copy our renderer re-encoded, on TikTok. We haven't counted it as proven. Most of the difference falls in a single week, and our newer files don't carry the encoder tag we would need to separate them cleanly. If you've measured re-encodes on TikTok yourself, I'd like to compare notes.

If you run several accounts

• Count zeros (10 views or fewer) per post, not averages per account. Averages hid this from us for weeks.
• Track how many times each source has already gone out on that platform, and read your zeros against it.
• Compare inside the same week before you believe any lever.
• Expect one platform's rule to be wrong on another.

The tool these posts went out through is Foundry: a Mac app plus a CLI and an agent skill that posts to your own accounts from your own iPhones, 7 days free at https://runfoundry.app. If you'd rather we run it for your app on our phones, that's at https://runfoundry.app/book.

What has your own data said about reposting? I'm curious whether anyone has seen Instagram forget a clip, and after how long.