Ranking

How to log your model schema for ranking models

Ranking Model Overview

There are four key ranking model use cases to consider:

  • Search Ranking

  • Collaborative Filtering Recommender Systems

  • Content Filtering Recommender Systems

  • Classification-Based Ranking Models

Different metrics are used for ranking model evaluation based on your model use case, score, and label availability. The case determines the available performance metrics. Click here for all valid model types and metric combinations.

Ranking CasesExample Use CaseExpected FieldsPerformance Metrics

Model predicts score used to rank

rank, relevance score

Model predicts binary actions a user can take which is used to rank

rank, relevance_labels

Model predicts multiple actions a user can take which is used to rank

rank, relevance_labels (list of strings)

Model can also be evaluated using AUC + LogLoss

Ranking Case 2 or 3, prediction score

NDCG, GroupAUC, MAP, MRR, AUC, PR-AUC, Log Loss

General Ranking Model Schema

Ranking models have a few unique model schema fields that help Arize effectively monitor, trace, and visualize your ranking model data.

  • Prediction Group ID: A subgroup of prediction data. Max 100 ranked items within each group

  • Rank: Unique value within each prediction group (1-100)

  • Relevancy Score/Label: Ground truth score/label associated with the model

Case 1: Ranking with Relevance Score

In the ranking model context, a relevance score is the numerical score used to rank items in a list. For example, the higher the relevance_score, the more important the item is. Relevancy scores often represent probabilities of an engagement or action such as probability of a click or purchase.

rank and relevance_score are required to compute rank-aware evaluation metrics on your model.

Ranking Model FieldsData TypeExample

rank

int from 1-100

1

relevance_score

numeric (float | int)

0.5

prediction_group_id

string limited to 128 characters

148

Code Example

Example Row

statepricesearch_idrankrelevance_scoreprediction_ts

ca

98

148

1

0.5

1618590882
# feature & tag columns can be optionally defined with typing:
tag_columns = TypedColumns(
    inferred=["name"],
    to_int=["zip_code", "age"]
)

schema = Schema(
    prediction_id_column_name="prediction_id",
    timestamp_column_name="prediction_ts",
    prediction_group_id_column_name = "search_id",
    rank_column_name = "rank",
    relevance_score_column_name = "relevance_score",
    feature_column_names=["state", "price"],
    tag_column_names=tag_columns,
)

response = arize_client.log(
    dataframe=df,
    model_id="ranking-relevance-score-batch-ingestion-tutorial",
    model_version="1.0",
    model_type=ModelTypes.RANKING,
    metrics_validation=[Metrics.RANKING],
    environment=Environments.PRODUCTION,
    schema=schema,
)

For more details on Python Batch API Reference, visit here:

pagePandas Batch Logging

Case 2: Ranking with Single Label

Since relevance_score is required to compute rank-aware evaluation metrics, Arize uses an attribution model to create a relevance_score based on your positive class and relevance_labels. Learn more about our attribution model here.

Ranking Model FieldsData TypeExample

rank

int from 1-100

1

relevance_labels

string

โ€œclickโ€

prediction_group_id

string limited to 128 characters

148

Code Example

Example Row

statepricesearch_idrankactual_relevancyprediction_ts

ca

98

148

1

"not relevant"

1618590882
# feature & tag columns can be optionally defined with typing:
tag_columns = TypedColumns(
    inferred=["name"],
    to_int=["zip_code", "age"]
)

schema = Schema(
    prediction_id_column_name="prediction_id",
    timestamp_column_name="prediction_ts",
    prediction_group_id_column_name = "search_id",
    rank_column_name = "rank",
    relevance_labels_column_name = "actual_relevancy",
    feature_column_names=["state", "price"],
    tag_column_names=tag_columns,
)

response = arize_client.log(
    dataframe=df,
    model_id="ranking-single-label-batch-ingestion-tutorial",
    model_version="1.0",
    model_type=ModelTypes.RANKING,
    metrics_validation=[Metrics.RANKING, Metrics.RANKING_LABEL],
    environment=Environments.PRODUCTION,
    schema=schema,
)

For more details on Python Batch API Reference, visit here:

pagePandas Batch Logging

Case 3: Ranking with Multiple Labels

In this case, each prediction on an item within a list is sent as an individual event while the possible relevance_labels can be multi-label (list) as ground truth can contain multiple events for an individual group or list.

Since relevance_score is required to compute rank-aware evaluation metrics, Arize uses an attribution model to create a relevance_score based on your positive class and relevance_labels. Learn more about our attribution model here.

Ranking Model FieldsData TypeExample

rank

int from 1-100

1

relevance_labels

list of strings

[โ€œclickโ€, โ€œfavoriteโ€, โ€œbuyโ€]

prediction_group_id

string limited to 128 characters

148

Code Example

Example Row

statepricesearch_idrankattributionsprediction_ts

ca

98

148

1

"click, favorite, buy"

1618590882
# feature & tag columns can be optionally defined with typing:
tag_columns = TypedColumns(
    inferred=["name"],
    to_int=["zip_code", "age"]
)

schema = Schema(
    prediction_id_column_name="prediction_id",
    timestamp_column_name="prediction_ts",
    prediction_group_id_column_name = "search_id",
    rank_column_name = "rank",
    relevance_labels_column_name = "attributions"
    feature_column_names=["state", "price"],
    tag_column_names=tag_columns,
)

response = arize_client.log(
    dataframe=df,
    model_id="ranking-multiple-labels-batch-ingestion-tutorial",
    model_version="1.0",
    model_type=ModelTypes.RANKING,
    metrics_validation=[Metrics.RANKING, Metrics.RANKING_LABEL],
    environment=Environments.PRODUCTION,
    schema=schema,
)

For more details on Python Batch API Reference, visit here:

pagePandas Batch Logging

Ranking Single or Multi-Label + AUC and LogLoss

For ranked lists based on a prediction of the action a user can take across single or multiple possible actions. AUC and LogLoss are computed based on prediction_score and relevance_labels (or default relevance_labels in the case of multi-label).

Ranking Model FieldsData TypeExample

rank

int from 1-100

1

prediction_score

float

0.5

prediction_group_id

string limited to 128 characters

148

Ranking Performance Metrics

Rank-aware evaluation metrics: NDCG @k (MAP @K & MRR coming soon)

Evaluation metrics: AUC, PR-AUC, LogLoss

NDCG @k

Normalized discounted cumulative gain (NDCG) is a rank-aware evaluation metric that measures a model's ability to rank query results in the order of the highest relevance (graded relevance). You can read more about how NDCG is computed here.

What is @k?

The k value determines the metric computation up to position k in a list.

Selecting Relevance Score or Label - Attribution Model

A relevance score is required to calculate rank-aware evaluation metrics. If your relevance_score is unavailable, the Arize platform will calculate a relevance_score using a simple attribution model with a prediction label and a relevance label. Arize computes a binary relevance value (0/1) based on the default positive class.

  • Positive class "buy" and relevance label is "buy" --> relevance will be attributed to 1.

  • Positive class "buy" and relevance label is else --> relevance will be attributed to 0.

  • Positive class "buy" and relevance labels are ["buy", "click", "scroll"] --> relevance will be attributed to sum([1,0,0])

Ranking Quick Definitions

Ranking model: Assigns a rank to each item in a prediction group (also known as a batch or query), across many possible groups.

Arize supports pointwise, pairwise, and listwise ranking models

Prediction Group: A group of predictions within which items are ranked.

Example: A user of a hotel booking site types in a search term (โ€œskiingโ€) and is presented with a list of results representing a single query

Rank: The predicted rank of an item in a prediction group (Integer between 1-100).

Example: Each item in the search prediction group has a rank determined by the model (i.e. Aspen is assigned rank=1, Tahoe is assigned rank=2, etc. based on input features and query features to the model)

Relevance Score (i.e. Actual Scores): The ground truth relevance score (numeric). Higher scores denote higher relevance.

Example: Each item in the search prediction group has a score determined by the action a user took on the item (i.e. โ€œclickingโ€ on an item indicates relevance score = 0.5, purchasing an item indicates relevance score = 1)

Rank-Aware Evaluation Metric: A rank-aware evaluation metric is an evaluation metric that gauges rank order and relevancy of predictions.

Rank-aware evaluation metrics include NDCG, MRR, and MAP. Note that MRR and MAP also require relevance_labels to be provided to be computed.

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