- A
Increase the complexity of the model by switching from a feedforward neural network to a gradient boosted tree ensemble, and then deploy without retraining.
Why wrong: Changing model architecture does not fix the data drift; the model still needs retraining on new data.
- B
Route all predictions to human reviewers until the model can be re-evaluated, and then manually correct the outputs.
Why wrong: This is not scalable and costly; a model retraining is a more efficient solution.
- C
Retrain the model using the most recent 3 months of data, including all new product categories, and deploy the updated model via a new Vertex AI endpoint.
Retraining with recent data addresses both covariate shift and concept drift, and is the standard approach for maintaining accuracy.
- D
Adjust the prediction threshold for the 'product_price' feature to account for the price shift, and monitor for another month.
Why wrong: Threshold adjustment only works for binary classification, not regression, and does not correct overall prediction accuracy.
Quick Answer
The answer is to retrain the model using the most recent three months of data and deploy it via a new Vertex AI endpoint. This is correct because the monitoring dashboard reveals both covariate shift—the mean of 'product_price' moving from $50 to $55—and concept drift, where the new 'electronics' category now makes up 20% of the data, fundamentally altering the relationship between features and demand. On the Google Professional Machine Learning Engineer exam, this scenario tests your ability to distinguish between drift types and select the most cost-effective, low-downtime retraining strategy; a common trap is choosing to adjust thresholds or switch to a more complex model, which fail to address the underlying data distribution change. Remember the key principle: when feature distributions and data composition shift significantly, retraining with recent representative data is the only scalable fix. A useful memory tip is “Shift the data, shift the model”—if the data’s story has changed, the model must be retrained, not patched.
PMLE Monitoring ML solutions Practice Question
This PMLE practice question tests your understanding of monitoring ml solutions. Read the scenario carefully and evaluate each option against the stated constraints before committing to an answer. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A retail company deployed a demand forecasting model using TensorFlow on Vertex AI Batch Prediction. The model runs weekly on a large dataset stored in BigQuery. Over the past month, the prediction accuracy has degraded significantly. The ML engineer reviews the monitoring dashboard and sees that the feature distribution for 'product_price' has shifted from a mean of $50 to $55, and the new product category 'electronics' now represents 20% of the data, whereas it was only 5% in training. The model was never retrained after initial deployment six months ago. The engineer also notices that the Vertex Explainable AI feature importance scores have changed: 'product_price' used to be the top feature (importance 0.35) but now ranks third (importance 0.20). The company requires minimal downtime and wants to improve accuracy as quickly as possible without incurring high costs from excessive retraining. Which course of action should the ML engineer take?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue:
"never"Why it matters: Absolute qualifier. True only if the statement has zero exceptions — be cautious of options that seem obvious but break down in edge cases.
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
Retrain the model using the most recent 3 months of data, including all new product categories, and deploy the updated model via a new Vertex AI endpoint.
The correct action is to retrain the model with the latest data because the feature distributions and data composition have changed significantly (covariate shift and concept drift). Simply using a more complex model (B) may overfit without addressing the underlying drift. Adjusting thresholds (C) is insufficient because the model's predictions are likely inaccurate. Sending all data to a human review (D) is costly and not scalable; retraining is the proper response.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Increase the complexity of the model by switching from a feedforward neural network to a gradient boosted tree ensemble, and then deploy without retraining.
Why it's wrong here
Changing model architecture does not fix the data drift; the model still needs retraining on new data.
- ✗
Route all predictions to human reviewers until the model can be re-evaluated, and then manually correct the outputs.
Why it's wrong here
This is not scalable and costly; a model retraining is a more efficient solution.
- ✓
Retrain the model using the most recent 3 months of data, including all new product categories, and deploy the updated model via a new Vertex AI endpoint.
Why this is correct
Retraining with recent data addresses both covariate shift and concept drift, and is the standard approach for maintaining accuracy.
Clue confirmation
The clue word "never" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Adjust the prediction threshold for the 'product_price' feature to account for the price shift, and monitor for another month.
Why it's wrong here
Threshold adjustment only works for binary classification, not regression, and does not correct overall prediction accuracy.
Common exam traps
Common exam trap: answer the scenario, not the keyword
Many certification questions include familiar terms but test a specific constraint. Read the exact wording before choosing an answer that is generally true but wrong for this case.
Detailed technical explanation
How to think about this question
This question should be treated as a scenario, not a definition check. Identify the problem, the constraint and the best action. Then compare each option against those facts.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
- Use explanations to understand the rule behind the answer.
TExam Day Tips
- Underline the problem statement mentally.
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which PMLE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
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FAQ
Questions learners often ask
What does this PMLE question test?
Monitoring ML solutions — This question tests Monitoring ML solutions — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: Retrain the model using the most recent 3 months of data, including all new product categories, and deploy the updated model via a new Vertex AI endpoint. — The correct action is to retrain the model with the latest data because the feature distributions and data composition have changed significantly (covariate shift and concept drift). Simply using a more complex model (B) may overfit without addressing the underlying drift. Adjusting thresholds (C) is insufficient because the model's predictions are likely inaccurate. Sending all data to a human review (D) is costly and not scalable; retraining is the proper response.
What should I do if I get this PMLE question wrong?
Identify which PMLE exam domain this question belongs to, then review the specific concept being tested. Practise related questions in that domain and focus on understanding why each wrong answer is tempting — not just why the correct answer is right.
Are there clue words in this question I should notice?
Yes — watch for: "never". Absolute qualifier. True only if the statement has zero exceptions — be cautious of options that seem obvious but break down in edge cases.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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Last reviewed: Jun 24, 2026
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