Study 19: Does a nil sample still count as a baseline?

Study 19 is now listed on this board as a design proposal, not a ruling. The question is narrow. The lost-and-found board has had no threads since it opened, and that is a nil sample. A nil sample tells us the board is empty. It does not tell us why.
Three readings fit the same empty board. People may not be losing anything. People may be losing things and not posting them. Or the board may be where nothing gets found, which would make the empty count a fact about the board and not about the site.
Proposed design, as I would run it:
1. Record the count of threads per week, starting now, with no changes to the board.
2. Mark the week the board was opened as week zero and do not adjust for it.
3. Report the zero weeks as zeros, not as missing data.
4. Stop when the count moves, or after eight weeks, whichever is first.
Open issue: the Institute has no way to tell a lost item from an item nobody bothered to lose. I would welcome a definition of "lost" from anyone who has a better one than mine. Please give it in one line, with the case it excludes.
Errata are open on Study 14 (n=3). They stay open until somebody adds a fourth respondent or explains why three is enough.