This weblog put up introduces the brand new Amazon Nova mannequin analysis options in Amazon SageMaker AI. This launch provides {custom} metrics help, LLM-based choice testing, log likelihood seize, metadata evaluation, and multi-node scaling for big evaluations.
The brand new options embrace:
- Customized metrics use the carry your individual metrics (BYOM) features to manage analysis standards in your use case.
- Nova LLM-as-a-Decide handles subjective evaluations via pairwise A/B comparisons, reporting win/tie/loss ratios and Bradley-Terry scores with explanations for every judgment.
- Token-level log chances reveal mannequin confidence, helpful for calibration and routing selections.
- Metadata passthrough retains per-row fields for evaluation by buyer phase, area, problem, or precedence stage with out additional processing.
- Multi-node execution distributes workloads whereas sustaining steady aggregation, scaling analysis datasets from hundreds to thousands and thousands of examples.
In SageMaker AI, groups can outline mannequin evaluations utilizing JSONL recordsdata in Amazon Easy Storage Service (Amazon S3), then execute them as SageMaker coaching jobs with management over pre- and post-processing workflows with outcomes delivered as structured JSONL with per-example and aggregated metrics and detailed metadata. Groups can then combine outcomes with analytics instruments like Amazon Athena and AWS Glue, or instantly route them into current observability stacks, with constant outcomes.
The remainder of this put up introduces the brand new options after which demonstrates step-by-step arrange evaluations, run choose experiments, seize and analyze log chances, use metadata for evaluation, and configure multi-node runs in an IT help ticket classification instance.
Options for mannequin analysis utilizing Amazon SageMaker AI
When selecting which fashions to carry into manufacturing, correct analysis methodologies require testing a number of fashions, together with personalized variations in SageMaker AI. To take action successfully, groups want similar check circumstances passing the identical prompts, metrics, and analysis logic to totally different fashions. This makes positive rating variations mirror mannequin efficiency, not analysis strategies.
Amazon Nova fashions which are personalized in SageMaker AI now inherit the total analysis infrastructure as base fashions making it a good comparability. Outcomes land as structured JSONL in Amazon S3, prepared for Athena queries or routing to your observability stack. Let’s talk about among the new options obtainable for mannequin analysis.
Carry your individual metrics (BYOM)
Commonplace metrics may not at all times suit your particular necessities. Customized metrics options leverage AWS Lambda features to deal with information preprocessing, output post-processing, and metric calculation. As an example, a customer support bot wants empathy and model consistency metrics; a medical assistant may require scientific accuracy measures. With {custom} metrics, you possibly can check what issues in your area.
On this characteristic, pre- and post-processor features are encapsulated in a Lambda perform that’s used to course of information earlier than inference to normalize codecs or inject context and to then calculate your {custom} metrics utilizing post-processing perform after the mannequin responds. Lastly, the outcomes are aggregated utilizing your selection of min, max, common, or sum, thereby providing better flexibility when totally different check examples carry various significance.
Multimodal LLM-as-a-judge analysis
LLM-as-a-judge automates choice testing for textual content in addition to multimodal duties utilizing Amazon Nova LLM-as-a-Decide fashions for response comparability. The system implements pairwise analysis: for every immediate, it compares baseline and challenger responses, working the comparability in each ahead and backward passes to detect positional bias. The output consists of Bradley-Terry chances (the probability one response is most well-liked over one other) with bootstrap-sampled confidence intervals, giving statistical confidence in choice outcomes.
Nova LLM-as-a-Decide fashions are purposefully personalized for judging associated analysis duties. Every judgment consists of pure language rationales explaining why the choose most well-liked one response over different, serving to with focused enhancements relatively than blind optimization. Nova LLM-as-a-Decide evaluates complicated reasoning duties like help ticket classification, the place nuanced understanding issues greater than easy key phrase matching.
The tie detection is equally precious, figuring out the place fashions have reached parity. Mixed with commonplace error metrics, you possibly can decide whether or not efficiency variations are statistically significant or inside noise margins; that is essential when deciding if a mannequin replace justifies deployment.
Use log likelihood for mannequin analysis
Log chances present mannequin confidence for every generated token, revealing insights into mannequin uncertainty and prediction high quality. Log chances help calibration research, confidence routing, and hallucination detection past primary accuracy. Token-level confidence helps determine unsure predictions for extra dependable methods.
A Nova analysis container with SageMaker AI mannequin analysis now captures token-level log chances throughout inference for uncertainty-aware analysis workflows. The characteristic integrates with analysis pipelines and supplies the inspiration for superior diagnostic capabilities. You possibly can correlate mannequin confidence with precise efficiency, implement high quality gates based mostly on uncertainty thresholds, and detect potential points earlier than they influence manufacturing methods. Add log likelihood seize by including the top_logprobs parameter to your analysis configuration:
When mixed with the metadata passthrough characteristic as mentioned within the subsequent part, log chances assist with stratified confidence evaluation throughout totally different information segments and use circumstances. This mixture supplies detailed insights into mannequin habits, so groups can perceive not simply the place fashions fail, however why they fail and the way assured they’re of their predictions giving them extra management over calibration.
Go metadata info when utilizing mannequin analysis
Customized datasets now help metadata fields when getting ready the analysis dataset. Metadata helps examine outcomes throughout totally different fashions and datasets. The metadata discipline accepts any string for tagging and evaluation with the enter information and eval outcomes. With the addition of the metadata discipline, the general schema per information level in JSONL file turns into the next:
Allow multi-node analysis
The analysis container helps multi-node analysis for quicker processing. Set the replicas parameter to allow multi-node analysis to a worth better than one.
Case examine: IT help ticket classification assistant
The next case examine demonstrates a number of of those new options utilizing IT help ticket classification. On this use case, fashions classify tickets as {hardware}, software program, community, or entry points whereas explaining their reasoning. This assessments each accuracy and rationalization high quality, and reveals {custom} metrics, metadata passthrough, log likelihood evaluation, and multi-node scaling in apply.

Dataset overview
The help ticket classification dataset incorporates IT help tickets spanning totally different precedence ranges and technical domains, every with structured metadata for detailed evaluation. Every analysis instance features a help ticket question, the system context, a structured response containing the anticipated class, the reasoning based mostly on ticket content material, and a pure language description. Amazon SageMaker Floor Reality responses embrace considerate explanations like Primarily based on the error message mentioning community timeout and the consumer's description of intermittent connectivity, this seems to be a community infrastructure difficulty requiring escalation to the community staff. The dataset consists of metadata tags for problem stage (straightforward/medium/exhausting based mostly on technical complexity), precedence (low/medium/excessive), and area class, demonstrating how metadata passthrough works for stratified evaluation with out post-processing joins.
Stipulations
Earlier than you run the pocket book, make sure that the provisioned setting has the next:
- An AWS account
- AWS Id and Entry Administration (IAM) permissions to create a Lambda perform, the power to run SageMaker coaching jobs inside the related AWS account within the earlier step, and browse and write permissions to an S3 bucket
- A growth setting with SageMaker Python SDK and the Nova {custom} analysis SDK (
nova_custom_evaluation_sdk)
Step 1: Put together the immediate
For our help ticket classification activity, we have to assess not solely whether or not the mannequin identifies the right class, but in addition whether or not it supplies coherent reasoning and adheres to structured output codecs to have a whole overview required in manufacturing methods. For crafting the immediate, we’re going to use Nova prompting finest practices.
System immediate design: Beginning with the system immediate, we set up the mannequin’s position and anticipated habits via a centered system immediate:
This immediate units clear expectations: the mannequin ought to act as a site knowledgeable, base selections on visible proof, and prioritize accuracy. By framing the duty as knowledgeable evaluation relatively than informal remark, we encourage extra considerate, detailed responses.
Question construction: The question template requests each classification and justification:
The specific request for reasoning is essential—it forces the mannequin to articulate its decision-making course of, serving to with analysis of rationalization high quality alongside classification accuracy. This mirrors real-world necessities the place mannequin selections usually should be interpretable for stakeholders or regulatory compliance.
Structured response format: We outline the anticipated output as JSON with three parts:
This construction helps the three-dimensional analysis technique we’ll talk about later on this put up:
- class discipline – Classification accuracy metrics (precision, recall, F1)
- thought discipline – Reasoning coherence analysis
- description discipline – Pure language high quality evaluation
By defining the response as parseable JSON, we assist with automated metric calculation via our {custom} Lambda features whereas sustaining human-readable explanations for mannequin selections. This immediate structure transforms analysis from easy proper/incorrect classification into a whole evaluation of mannequin capabilities. Manufacturing AI methods should be correct, explainable, and dependable of their output formatting—and our immediate design explicitly assessments all three dimensions. The structured format additionally facilitates the metadata-driven stratified evaluation we’ll use in later steps, the place we are able to correlate reasoning high quality with confidence scores and problem ranges throughout totally different breed classes.
Step 2: Put together the dataset for analysis with metadata
On this step, we’ll put together our help ticket dataset with metadata help to assist with stratified evaluation throughout totally different classes and problem ranges. The metadata passthrough characteristic retains {custom} fields full for detailed efficiency evaluation with out post-hoc joins. Let’s evaluation an instance dataset.
Dataset schema with metadata
For our help ticket classification analysis, we’ll use the improved gen_qa format with structured metadata:
Look at this additional: how can we mechanically generate structured metadata for every analysis instance? This metadata enrichment course of analyzes the content material to categorise activity varieties, assess problem ranges, and determine domains, creating the inspiration for stratified evaluation in later steps. By embedding this contextual info instantly into our dataset, we assist the Nova analysis pipeline hold these insights full, so we are able to perceive mannequin efficiency throughout totally different segments with out requiring complicated post-processing joins.
As soon as our dataset is enriched with metadata, we have to export it within the JSONL format required by the Nova analysis container.
The next export perform codecs our ready examples with embedded metadata in order that they’re prepared for the analysis pipeline, sustaining the precise schema construction wanted for the Amazon SageMaker processing workflow:
Step 3: Put together {custom} metrics to judge {custom} fashions
After getting ready and verifying your information adheres to the required schema, the following essential step is to develop analysis metrics code to evaluate your {custom} mannequin’s efficiency. Use Nova analysis container and the carry your individual metric (BYOM) workflow to manage your mannequin analysis pipeline with {custom} metrics and information workflows.
Introduction to BYOM workflow
With the BYOM characteristic, you possibly can tailor your mannequin analysis workflow to your particular wants with absolutely customizable pre-processing, post-processing, and metrics capabilities. BYOM provides you management over the analysis course of, serving to you to fine-tune and enhance your mannequin’s efficiency metrics in accordance with your challenge’s distinctive necessities.
Key duties for this classification drawback
- Outline duties and metrics: On this use case, mannequin analysis requires three duties:
- Class prediction accuracy: This may assess how precisely the mannequin predicts the right class for given inputs. For this we’ll use commonplace metrics corresponding to accuracy, precision, recall, and F1 rating to quantify efficiency.
- Schema adherence: Subsequent, we additionally wish to be sure that the mannequin’s outputs conform to the required schema. This step is essential for sustaining consistency and compatibility with downstream purposes. For this we’ll use validation strategies to confirm that the output format matches the required schema.
- Thought course of coherence: Subsequent, we additionally wish to consider the coherence and reasoning behind the mannequin’s selections. This includes analyzing the mannequin’s thought course of to assist validate predictions are logically sound. Strategies corresponding to consideration mechanisms, interpretability instruments, and mannequin explanations can present insights into the mannequin’s decision-making course of.
The BYOM characteristic for evaluating {custom} fashions requires constructing a Lambda perform.
- Configure a {custom} layer in your Lambda perform. Within the GitHub launch, discover and obtain the pre-built nova-custom-eval-layer.zip file.
- Use the next command to add the {custom} Lambda layer:
- Add the printed layer and
AWSLambdaPowertoolsPythonV3-python312-arm64(or comparable AWS layer based mostly on Python model and runtime model compatibility) to your Lambda perform to make sure all obligatory dependencies are put in. - For growth of the Lambda perform, import two key dependencies: one for importing the preprocessor and postprocessor decorators and one to construct the
lambda_handler:
- Add the preprocessor and postprocessor logic.
- Preprocessor logic: Implement features that manipulate the information earlier than it’s handed to the inference server. This may embrace immediate manipulations or different information preprocessing steps. The pre-processor expects an occasion dictionary (dict), a sequence of key worth pairs, as enter:
Instance:
- Postprocessor logic: Implement features that course of the inference outcomes. This may contain parsing fields, including {custom} validations, or calculating particular metrics. The postprocessor expects an occasion dict as enter which has this format:
- Preprocessor logic: Implement features that manipulate the information earlier than it’s handed to the inference server. This may embrace immediate manipulations or different information preprocessing steps. The pre-processor expects an occasion dictionary (dict), a sequence of key worth pairs, as enter:
- Outline the Lambda handler, the place you add the pre-processor and post-processor logics, earlier than and after inference respectively.

Step 4: Launch the analysis job with {custom} metrics
Now that you’ve constructed your {custom} processors and encoded your analysis metrics, you possibly can select a recipe and make obligatory changes to ensure the earlier BYOM logic will get executed. For this, first select carry your individual information recipes from the general public repo, and ensure the next code modifications are made.
- Guarantee that the processor key’s added on to the recipe with appropriate particulars:
- lambda-arn: The Amazon Useful resource Identify (ARN) for a buyer Lambda perform that handles pre-processing and post-processing
- preprocessing: Whether or not so as to add {custom} pre-processing operations
- post-processing: Whether or not so as to add {custom} post-processing operations
- aggregation: In-built aggregation perform to select from.
min, max, common, or sum
- Launch a coaching job with an analysis container:
Step 5: Use metadata and log chances to calibrate the accuracy
You may as well embrace log likelihood as an inference config variable to assist conduct logit-based evaluations. For this we are able to cross top_logprobs underneath inference within the recipe:
top_logprobs signifies the variety of most probably tokens to return at every token place every with an related log likelihood. This worth should be an integer from 0 to twenty. Logprobs include the thought-about output tokens and log chances of every output token returned within the content material of message.
As soon as the job runs efficiently and you’ve got the outcomes, you will discover the log chances underneath the sector pred_logprobs. This discipline incorporates the thought-about output tokens and log chances of every output token returned within the content material of message. Now you can use the logits produced to do calibration in your classification activity. The log chances of every output token may be helpful for calibration, to regulate the predictions and deal with these chances as confidence rating.
Step 6: Failure evaluation on low confidence prediction
After calibrating our mannequin utilizing metadata and log chances, we are able to now determine and analyze failure patterns in low-confidence predictions. This evaluation helps us perceive the place our mannequin struggles and guides focused enhancements.
Loading outcomes with log chances
Now, let’s study intimately how we mix the inference outputs with detailed log likelihood information from the Amazon Nova analysis pipeline. This helps us carry out confidence-aware failure evaluation by merging the prediction outcomes with token-level uncertainty info.
Generate a confidence rating from log chances by changing the logprobs to chances and utilizing the rating of the primary token within the classification response. We solely use the primary token as we all know subsequent tokens within the classification would align the category label. This step creates downstream high quality gates during which we may route low confidence scores to human evaluation, have a view into mannequin uncertainty to validate if the mannequin is “guessing,” stopping hallucinations from reaching customers, and later permits stratified evaluation.
Preliminary evaluation
Subsequent, we carry out stratified failure evaluation, which mixes confidence scores with metadata classes to determine particular failure patterns. This multi-dimensional evaluation reveals failure modes throughout totally different activity varieties, problem ranges, and domains. Stratified failure evaluation systematically examines low-confidence predictions to determine particular patterns and root causes. It first filters predictions beneath the arrogance threshold, then conducts multi-dimensional evaluation throughout metadata classes to pinpoint the place the mannequin struggles most. We additionally analyze content material patterns in failed predictions, searching for uncertainty language and categorizing error varieties (JSON format points, size issues, or content material errors) earlier than producing insights that inform groups precisely what to repair.
Preview preliminary outcomes
Now let’s evaluation our preliminary outcomes displaying what was parsed out.
Step 7: Scale the evaluations on multi-node prediction
After figuring out failure patterns, we have to scale our analysis to bigger datasets for testing. Nova analysis containers now help multi-node analysis to enhance throughput and velocity by configuring the variety of replicas wanted within the recipe.
The Nova analysis container handles multi-node scaling mechanically whenever you specify multiple duplicate in your analysis recipe. Multi-node scaling distributes the workload throughout a number of nodes whereas sustaining the identical analysis high quality and metadata passthrough capabilities.
End result aggregation and efficiency evaluation
The Nova analysis container mechanically handles outcome aggregation from a number of replicas, however we are able to analyze the scaling effectiveness and restrict metadata-based evaluation to the distributed analysis.
Multi-node analysis makes use of the Nova analysis container’s built-in capabilities via the replicas parameter, distributing workloads mechanically and aggregating outcomes whereas maintaining all metadata-based stratified evaluation capabilities. The container handles the complexity of distributed processing, serving to groups to scale from hundreds to thousands and thousands of examples by growing the duplicate rely.
Conclusion
This instance demonstrated Nova mannequin analysis fundamentals exhibiting the capabilities of recent characteristic releases for the Nova analysis container. We confirmed how us utilization of {custom} metrics (BYOM) with domain-specific assessments can drive deep insights. Then defined extract and use log chances to disclose mannequin uncertainty easing the implementation of high quality gates and confidence-based routing. Then confirmed how the metadata passthrough functionality is used downstream for stratified evaluation, pinpointing the place fashions battle and the place to focus enhancements. We then recognized a easy method to scale these methods with multi-node analysis capabilities. Together with these options in your analysis pipeline can assist you make knowledgeable selections on which fashions to undertake and the place customization must be utilized.
Get began now with the Nova analysis demo pocket book which has detailed executable code for every step above, from dataset preparation via failure evaluation, supplying you with a baseline to change so you possibly can consider your individual use case.
Try the Amazon Nova Samples repository for full code examples throughout quite a lot of use circumstances.
Concerning the authors
Tony Santiago is a Worldwide Accomplice Options Architect at AWS, devoted to scaling generative AI adoption throughout International Techniques Integrators. He focuses on resolution constructing, technical go-to-market alignment, and functionality growth—enabling tens of hundreds of builders at GSI companions to ship AI-powered options for his or her prospects. Drawing on greater than 20 years of world know-how expertise and a decade with AWS, Tony champions sensible applied sciences that drive measurable enterprise outcomes. Outdoors of labor, he’s captivated with studying new issues and spending time with household.
Akhil Ramaswamy is a Worldwide Specialist Options Architect at AWS, specializing in superior mannequin customization and inference on SageMaker AI. He companions with international enterprises throughout numerous industries to unravel complicated enterprise issues utilizing the AWS generative AI stack. With experience in constructing production-grade agentic methods, Akhil focuses on growing scalable go-to-market options that assist enterprises drive innovation whereas maximizing ROI. Outdoors of labor, you will discover him touring, figuring out, or having fun with a pleasant e book.
Anupam Dewan is a Senior Options Architect working in Amazon Nova staff with a ardour for generative AI and its real-world purposes. He focuses on constructing, enabling, and benchmarking AI purposes for GenAI prospects in Amazon. With a background in AI/ML, information science, and analytics, Anupam helps prospects study and make Amazon Nova work for his or her GenAI use circumstances to ship enterprise outcomes. Outdoors of labor, you will discover him climbing or having fun with nature.

