# Some duplicate are not detected, what can I do?

## What to Do If Legitimate Duplicates Are Not Being Detected in Delpha

If some **valid duplicates** are not flagged by Delpha's duplicate detection process, there are several ways to **improve match detection and scoring accuracy**.

This article outlines the key configurations you can adjust to optimize the detection process and identify more true duplicate pairs.

### 1. Add Additional [Screen Fields](https://help.delpha.io/use-cases-setup/duplicate/duplicate-detection#advanced-settings-optional)

#### What Are Screening Fields?

Screening fields are used during the **initial filtering phase** to decide whether two records should even be considered as a potential match. By default, this relies heavily on the **Name** field.

If two records differ significantly in name but match on other key fields (e.g., email, phone, domain), they may be missed.

#### How Screening Fields Help

* ✅ **Adding relevant fields** (e.g., Email, LinkedIn URL) increases the chance of catching real duplicates that don't match on name alone.
* ⚠️ **Using too many screening fields** can increase processing time and generate low-confidence pairs (**false positives**).

> **Example:** Add `Website` and `LinkedIn URL` as screening fields for Company duplicate detection or add Email as screening for Contact duplicate detection

<table><thead><tr><th width="92">Field</th><th width="172">Contact A</th><th width="182">Contact B</th><th>Screening</th></tr></thead><tbody><tr><td>Name</td><td><mark style="color:orange;">William</mark> <mark style="color:orange;">SMITH</mark> </td><td>Bill Charles Henry  <mark style="color:orange;">SMITH</mark> - JOHNSON </td><td><p>Default Screening: based on the <strong>Name</strong></p><p>⇒ NOT DETECTED, names are too different</p></td></tr><tr><td>Email</td><td><mark style="color:orange;">william@acme.com</mark></td><td><mark style="color:orange;">william@acme.com</mark></td><td><p>Screen Fields: <strong>Email</strong> </p><p>⇒ DETECTED -> the pair Contact A - Contact B is sent to the scoring process</p></td></tr></tbody></table>

### 2. Review and Adjust [Fields detection](https://help.delpha.io/delpha-for-salesforce/use-cases-setup/duplicate/duplicate-detection) Rules

#### [Mandatory vs. Optional rules](https://help.delpha.io/delpha-for-salesforce/how-to-faq/how-does-the-duplicate-scoring-work#impact-of-mandatory-setting-on-the-score)

* **Mandatory fields** reduce false positives by requiring data in both records for scoring.
* **Optional fields** allow records with missing data to still contribute to a pair’s score.

> 📌 **Tip:** Consider relaxing some fields from Mandatory → Optional to allow more flexible matching.

#### Add New Optional Fields

* Introducing new fields as **optional comparison points** (like `Industry`, `Phone`, `Region`) can help **boost the match score** and uncover missed duplicates.

### 3. Improve Your Underlying Data Quality

Duplicate detection accuracy **directly depends** on the **quality and completeness** of the data being evaluated.

#### Steps to Take:

* Run **Data Quality assessments** in the **Data Steward View**
* [Apply Delpha’s **recommended values** to improve data validity, consistency, and completeness](https://help.delpha.io/delpha-for-salesforce/delpha-apps/delpha-data-quality/data-quality-steward-view)
* Ensure key fields used in deduplication (e.g., `Name`, `Email`, `LinkedIn`) are up to date

## Summary

| Improvement Area     | What It Does                                 | Recommendation                                 |
| -------------------- | -------------------------------------------- | ---------------------------------------------- |
| **Screening Fields** | Helps include more potential duplicate pairs | Use sparingly                                  |
| **Detection Rules**  | Impacts score calculation logic              | Adjust Mandatory settings, add Optional fields |
| **Data Quality**     | Better input = better detection              | Apply fixes from Steward View                  |

{% hint style="success" %}
If you identify the undetected pair, you can utilize the [on-demand merge feature](https://help.delpha.io/delpha-for-salesforce/how-to-faq/delpha-duplicate/how-can-i-merge-records-on-demand).
{% endhint %}