Part B: Generate fraud predictions

Fraud prediction is an evaluation of fraud for a business activity (event). Amazon Fraud Detector uses detectors to generate fraud prediction. A detector contains detection logic, such as models and rules, for a specific event that you want to evaluate for fraud. Detection logic uses rules to tell Amazon Fraud Detector how to interpret the data associated with the model. In this tutorial, you evaluate the account registration event using the account registration example dataset that you uploaded earlier.

In Part A, you created, trained, and deployed your model. In Part B, you build a detector for the sample_registration event type, add the deployed model, create rules and a rule execution order, and then create and activate a version of the detector that you use to generate fraud predictions.

Step 1: Build detector

To create detector

1. In the left navigation pane of the Amazon Fraud Detector console, choose Detectors.

2. Choose Create detector.

3. In the Define detector details page, enter sample_detector for detector name. Optionally, enter a description for the detector, such as my sample fraud detector.

4. For Event Type, select sample_registration. This is the event that you created in Part A of this tutorial.

5. Choose Next.

Step 2: Add model

If you completed Part A of this tutorial, then you likely already have an Amazon Fraud Detector model that's available to add to your detector. If you didn't already create a model, go to Part A and complete the steps to create, train, and deploy a model and then continue with Part B.

1. In the Add model - optional, choose Add Model.

2. In the Add model page, for Select model, choose the Amazon Fraud Detector model name that you deployed earlier. For Select version, choose the model version of the deployed model.

3. Choose Add model.

4. Choose Next.

Step 3: Add rules

A rule is a condition that tells Amazon Fraud Detector how to interpret model performance score when evaluating for fraud prediction. For this tutorial, you create three rules: high_fraud_risk, medium_fraud_risk, and low_fraud_risk.

1. In the Add rules page, under Define a rule, enter high_fraud_risk for the rule name and under Description - optional, enter This rule captures events with a high ML model score as the description for the rule.

2. In Expression, enter the following rule expression using the Amazon Fraud Detector simplified rule expression language:

   $sample_fraud_detection_model_insightscore > 900

3. In Outcomes, choose Create a new outcome. An outcome is the result from a fraud prediction and is returned if the rule matches during an evaluation.

4. In Create a new outcome, enter verify_customer as the outcome name. Optionally, enter a description.

5. Choose Save outcome.

6. Choose Add rule to run the rule validation checker and save the rule. After it's created, Amazon Fraud Detector makes the rule available for use in your detector.

7. Choose Add another rule, and then choose the Create rule tab.

8. Repeat this process twice more to create your medium_fraud_risk and low_fraud_risk rules using the following rule details:

   • medium_fraud_risk

     Rule name: medium_fraud_risk

     Outcome: review

     Expression:

     $sample_fraud_detection_model_insightscore <= 900 and

     $sample_fraud_detection_model_insightscore > 700

   • low_fraud_risk

     Rule name: low_fraud_risk

     Outcome: approve

     Expression:

     $sample_fraud_detection_model_insightscore <= 700

   These values are examples used for this tutorial. When you create rules for your own detector, use values that are appropriate for your model and your use case,

9. After you have created all three rules, choose Next.

   For more information about creating and writing rules, see Rules and Rule language reference.

Step 4: Configure rule execution and rule order

The rule execution mode for the rules that are included in the detector determines if all the rules you define are evaluated, or if rule evaluation stops at the first matched rule. And the rule order determines the order that you want the rule to be run in.

The default rule execution mode is FIRST_MATCHED.

First matched

First matched rule execution mode returns the outcomes for the first matching rule based on defined rule order. If you specify FIRST_MATCHED, Amazon Fraud Detector evaluates rules sequentially, first to last, stopping at the first matched rule. Amazon Fraud Detector then provides the outcomes for that single rule.

The order that you run rules in can affect the resulting fraud prediction outcome. After you have created your rules, re-order the rules to run them in the desired order by following these steps:

If your high_fraud_risk rule isn't already on the top of your rule list, choose Order, and then choose 1. This moves high_fraud_risk to the first position.

Repeat this process so that your medium_fraud_risk rule is in the second position and your low_fraud_risk rule is in the third position.

All matched

All matched rule execution mode returns outcomes for all matched rules, regardless of rule order. If you specify ALL_MATCHED, Amazon Fraud Detector evaluates all rules and returns the outcomes for all matched rules.

Select FIRST_MATCHED for this tutorial and then choose Next.

Step 5: Review and create detector version

A detector version defines the specific models and rules that are used for generating fraud predictions.

1. In the Review and create page, review the detector details, models, and rules that you configured. If you need to make any changes, choose Edit next to the corresponding section.

2. Choose Create detector. After it's created, the first version of your detector appears in the Detector versions table with Draft status.

   You use the Draft version to test your Detector.

Step 6: Test and activate detector version

In the Amazon Fraud Detector console, you can test the logic of your detector using a mock data with the Run test feature. For this tutorial, you can use account registration data from the example dataset.

1. Scroll to Run test at the bottom of the Detector version details page.

2. For Event metadata, enter a timestamp of when the event occurred and enter a unique identifier for the entity performing the event. For this tutorial, select a date from the date picker for timestamp, and enter “1234” for the Entity ID.

3. For Event variable, enter the variable values that you want to test. For this tutorial, you only need the ip_address and email_address fields. This is because they are the inputs that are used to train your Amazon Fraud Detector model. You can use the following example values. This assumes that you used the suggested variable names:

   • ip_address: 205.251.233.178

   • email_address: [e-mail]

4. Choose Run test.

5. Amazon Fraud Detector returns the fraud prediction outcome based on the rule execution mode. If the rule execution mode is FIRST_MATCHED, the returned outcome corresponds to the first rule that matched. The first rule is the rule with the highest priority. It's matched if it's evaluated as true. If the rule execution mode is ALL_MATCHED, the returned outcome corresponds to all rules that matched. That means that they're all evaluated to be true. Amazon Fraud Detector also returns the model score for any models added to your detector.

   You can change the inputs and run couple of tests to see different outcomes. You can use the ip_address and email_address values from your example dataset for the tests and check if the outcomes are as expected.

6. When you're satisfied with how the detector is working, promote it from Draft to Active. Doing so makes the detector available for use in real-time fraud detection.

   On the Detector version details page, choose Actions, Publish, Publish version. This changes the status of the detector from Draft to Active.

   At this point, your model and the associated detector logic are ready to evaluate online activities for fraud in real time using the Amazon Fraud Detector GetEventPrediction API. You can also evaluate events offline using a CSV input file and the CreateBatchPredictionJob API. For more information about fraud prediction, see Fraud predictions

By completing this tutorial, you did the following:

• Uploaded an example event dataset to Amazon S3.

• Created and trained an Amazon Fraud Detector fraud detection model using the example dataset.

• Viewed the model performance score and other performance metrics that Amazon Fraud Detector generated.

• Deployed the fraud detection model.

• Created a detector and added the deployed model.

• Added rules, the rule execution order, and outcomes to the detector.

• Tested the detector by providing different inputs and checking if the rules and rule execution order worked as expected.

• Activated the detector by publishing it.