Why the wall is what makes the programme work
An executive who suspects the board will read his results gives a worse sample of himself. The test is deferred, the questionnaire is answered carefully, and the one marker that matters goes unmentioned. Confidentiality is not a courtesy here — it is the measurement instrument itself.
The wall is what makes the data true, and true data is what the entire financial case stands on. So the promise is absolute, and it survives seniority: your results are never shown to your employer, and if your employer asks, the office declines.