Evaluate a model response against a reference (ground truth) using the ROUGE metric

This code sample demonstrates how to use Vertex AI to compute ROUGE metrics for evaluating text summarization models. It shows how to define an evaluation task and calculate ROUGE scores for multiple generated summaries against a reference summary.

Explore further

For detailed documentation that includes this code sample, see the following:

• Gen AI evaluation service API

Code sample

Go

Before trying this sample, follow the Go setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI Go API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import (
	"context"
	"fmt"
	"io"

	aiplatform "cloud.google.com/go/aiplatform/apiv1beta1"
	aiplatformpb "cloud.google.com/go/aiplatform/apiv1beta1/aiplatformpb"
	"google.golang.org/api/option"
)

// getROUGEScore evaluates a model response against a reference (ground truth) using the ROUGE metric
func getROUGEScore(w io.Writer, projectID, location string) error {
	// location = "us-central1"
	ctx := context.Background()
	apiEndpoint := fmt.Sprintf("%s-aiplatform.googleapis.com:443", location)
	client, err := aiplatform.NewEvaluationClient(ctx, option.WithEndpoint(apiEndpoint))

	if err != nil {
		return fmt.Errorf("unable to create aiplatform client: %w", err)
	}
	defer client.Close()

	modelResponse := `
The Great Barrier Reef, the world's largest coral reef system located in Australia,
is a vast and diverse ecosystem. However, it faces serious threats from climate change,
ocean acidification, and coral bleaching, endangering its rich marine life.
`
	reference := `
The Great Barrier Reef, the world's largest coral reef system, is
located off the coast of Queensland, Australia. It's a vast
ecosystem spanning over 2,300 kilometers with thousands of reefs
and islands. While it harbors an incredible diversity of marine
life, including endangered species, it faces serious threats from
climate change, ocean acidification, and coral bleaching.
`
	req := aiplatformpb.EvaluateInstancesRequest{
		Location: fmt.Sprintf("projects/%s/locations/%s", projectID, location),
		MetricInputs: &aiplatformpb.EvaluateInstancesRequest_RougeInput{
			RougeInput: &aiplatformpb.RougeInput{
				// Check the API reference for the list of supported ROUGE metric types:
				// https://cloud.google.com/vertex-ai/docs/reference/rpc/google.cloud.aiplatform.v1beta1#rougespec
				MetricSpec: &aiplatformpb.RougeSpec{
					RougeType: "rouge1",
				},
				Instances: []*aiplatformpb.RougeInstance{
					{
						Prediction: &modelResponse,
						Reference:  &reference,
					},
				},
			},
		},
	}

	resp, err := client.EvaluateInstances(ctx, &req)
	if err != nil {
		return fmt.Errorf("evaluateInstances failed: %v", err)
	}

	fmt.Fprintln(w, "evaluation results:")
	fmt.Fprintln(w, resp.GetRougeResults().GetRougeMetricValues())
	// Example response:
	// [score:0.6597938]

	return nil
}

Python

Before trying this sample, follow the Python setup instructions in the Vertex AI quickstart using client libraries. For more information, see the Vertex AI Python API reference documentation.

To authenticate to Vertex AI, set up Application Default Credentials. For more information, see Set up authentication for a local development environment.

import pandas as pd

import vertexai
from vertexai.preview.evaluation import EvalTask

# TODO(developer): Update & uncomment line below
# PROJECT_ID = "your-project-id"
vertexai.init(project=PROJECT_ID, location="us-central1")

reference_summarization = """
The Great Barrier Reef, the world's largest coral reef system, is
located off the coast of Queensland, Australia. It's a vast
ecosystem spanning over 2,300 kilometers with thousands of reefs
and islands. While it harbors an incredible diversity of marine
life, including endangered species, it faces serious threats from
climate change, ocean acidification, and coral bleaching."""

# Compare pre-generated model responses against the reference (ground truth).
eval_dataset = pd.DataFrame(
    {
        "response": [
            """The Great Barrier Reef, the world's largest coral reef system located
        in Australia, is a vast and diverse ecosystem. However, it faces serious
        threats from climate change, ocean acidification, and coral bleaching,
        endangering its rich marine life.""",
            """The Great Barrier Reef, a vast coral reef system off the coast of
        Queensland, Australia, is the world's largest. It's a complex ecosystem
        supporting diverse marine life, including endangered species. However,
        climate change, ocean acidification, and coral bleaching are serious
        threats to its survival.""",
            """The Great Barrier Reef, the world's largest coral reef system off the
        coast of Australia, is a vast and diverse ecosystem with thousands of
        reefs and islands. It is home to a multitude of marine life, including
        endangered species, but faces serious threats from climate change, ocean
        acidification, and coral bleaching.""",
        ],
        "reference": [reference_summarization] * 3,
    }
)
eval_task = EvalTask(
    dataset=eval_dataset,
    metrics=[
        "rouge_1",
        "rouge_2",
        "rouge_l",
        "rouge_l_sum",
    ],
)
result = eval_task.evaluate()

print("Summary Metrics:\n")
for key, value in result.summary_metrics.items():
    print(f"{key}: \t{value}")

print("\n\nMetrics Table:\n")
print(result.metrics_table)
# Example response:
#
# Summary Metrics:
#
# row_count:      3
# rouge_1/mean:   0.7191161666666667
# rouge_1/std:    0.06765143922270488
# rouge_2/mean:   0.5441118566666666
# ...
# Metrics Table:
#
#                                        response                         reference  ...  rouge_l/score  rouge_l_sum/score
# 0  The Great Barrier Reef, the world's ...  \n    The Great Barrier Reef, the ...  ...       0.577320           0.639175
# 1  The Great Barrier Reef, a vast coral...  \n    The Great Barrier Reef, the ...  ...       0.552381           0.666667
# 2  The Great Barrier Reef, the world's ...  \n    The Great Barrier Reef, the ...  ...       0.774775           0.774775

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