Final answer:
The audit firm's failure to follow GAAS is likely a violation of due professional care due to their lack of diligence, despite being qualified. This reflects a similar issue to the Stapel case, where researchers did not adequately scrutinize data.
Step-by-step explanation:
When the firm of Schultz and Gleason took on the audit of Bagel Bakers but did not properly follow Generally Accepted Auditing Standards (GAAS), despite having the qualifications and training needed, this most likely constitutes a violation of due professional care. Given that they had the necessary expertise, their failure to adhere to GAAS implies a lack of due diligence in their approach to the audit, rather than a lack of competence, planning or data sufficiency.
Researchers, like auditors, have the responsibility to ensure that proper methods are followed. A comparison can be made with the investigation of Stapel's fraud, which revealed that co-authors often trusted Stapel's data without adequate scrutiny, highlighting a shortfall in due professional care. Similarly, Schultz and Gleason's missteps suggest complacency in their dedication to the audit process.