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CISA · Question #205

An IS auditor is reviewing a machine learning model that predicts the likelihood that a user will watch a certain movie. Which of the following would be of GREATEST concern to the auditor?

The correct answer is A. The data set for training the model was obtained from an unreliable source. Unreliable training data is the greatest concern because ML models are only as trustworthy as the data they learn from - if the source is compromised, biased, or fabricated, every prediction the model makes is built on a flawed foundation, and no amount of testing can salvage…

Submitted by devops_kid· Apr 18, 2026Information Systems Acquisition, Development, and Implementation

Question

An IS auditor is reviewing a machine learning model that predicts the likelihood that a user will watch a certain movie. Which of the following would be of GREATEST concern to the auditor?

Options

  • AThe data set for training the model was obtained from an unreliable source
  • BWhen the model was tested with data drawn from a different population, the accuracy decreased
  • CAn open source programming language was used to develop the model
  • DThe model was tested with data drawn from the same population as the training data

How the community answered

(45 responses)
  • A
    42% (19)
  • B
    29% (13)
  • C
    9% (4)
  • D
    20% (9)

Explanation

Unreliable training data is the greatest concern because ML models are only as trustworthy as the data they learn from - if the source is compromised, biased, or fabricated, every prediction the model makes is built on a flawed foundation, and no amount of testing can salvage it ("garbage in, garbage out").

Why the distractors are wrong:

  • B describes expected ML behavior - a model trained on one population performing worse on a different population is a known limitation, not a red flag, and can be addressed through re-training or scope adjustments.
  • C is irrelevant to model reliability; open source languages like Python and R are industry-standard tools for ML development and carry no inherent risk.
  • D is actually acceptable practice - testing on data drawn from the same population (but a different sample) is normal; the concern would be testing on the exact same records used for training, which D does not say.

Memory tip: In IS audit questions, always trace the problem to its root. For ML models, data quality is the root - if the soil is poisoned, the tree will be too, regardless of how well you tend the branches.

Topics

#Machine Learning Audit#Data Quality#Model Reliability#Audit Risk

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