# How to create a Master selection custom rule - Advanced

## How to Use a Custom Formula for Complex Master Record Selection

In some cases, selecting a master record based on a simple value comparison (like highest number or checkbox = true) isn’t enough. When your business logic is more advanced, the best approach is to create a **custom formula field** that **scores each record** based on multiple conditions.

This score is then used to **sort the duplicate pair** and select the master record.

## When to Use a Formula-Based Master Rule

Use a formula when:

* You need to prioritize based on a combination of **picklists, metrics, and dates**
* You want to handle **tie-breaker logic** across several layers
* Your logic changes based on **status**, **recency**, or **business value**

## Step-by-Step Setup

### **1. Create a Custom Formula Field**

* Object: Account, Contact, or Lead (where duplicates occur)
* Field Type: Formula
* Return Type: Number
* Example API Name: `MyDuplicateMasterRecordScore__c`

### **2. Add Your Logic in the Formula Field**

Here’s a complete example based on business rules:

```salesforce
salesforceCopyEditCASE(
   Status__c,
   "Customer", 10000,      /* Rule 1: Always prioritize Customer */
   "Prospect", 5000,       /* Rule 3: Prospect over Target */
   "Target", 1000,
   0
) +
IF(
   AND(Status__c = "Customer", NOT(ISBLANK(Number_of_Opportunities__c))),
   Number_of_Opportunities__c * 10,  /* Rule 2: More Opps wins among Customers */
   0
) +
IF(
   AND(Status__c = "Prospect", Last_Touchpoint_Date__c < TODAY() - 180),
   -4000,  /* Penalize cold Prospects */
   0
) +
(100000000 - CreatedDate) /* Rule 4: Prefer oldest if all else equal */
```

This formula returns a numeric score. The record with the **highest score** becomes the master during the merge.

### **3. Use It in Delpha Duplicate Settings**

In **Delpha Setup → Duplicate Settings**, set the **Master Rule** to:

```
MyDuplicateMasterRecordScore__c DESC, CreatedDate ASC
```

#### What This Covers

* Rule 1: Always select **Customer** as master
* Rule 2: Among Customers, prioritize by **# of Opportunities**
* Rule 3: Prefer **Prospect** over **Target**, unless the Prospect is outdated
* Rule 4: Use **Created Date** as fallback


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