# Data Assistant always suggesting only one expectation

**URL:** <https://discourse.greatexpectations.io/t/data-assistant-always-suggesting-only-one-expectation/1717>\
**Category:** GX Core Support\
**Created:** [April 19, 2024, 5:26pm UTC](https://discourse.greatexpectations.io/t/data-assistant-always-suggesting-only-one-expectation/1717 "2024-04-19T17:26:36Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![sounzbreaker](https://avatars.discourse-cdn.com/v4/letter/s/ac8455/32.png) [@sounzbreaker](https://discourse.greatexpectations.io/u/sounzbreaker)\
**Post date:** [April 19, 2024, 5:26pm UTC](https://discourse.greatexpectations.io/t/data-assistant-always-suggesting-only-one-expectation/1717/1 "2024-04-19T17:26:36Z")

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Hello,  
I’ve tried with different datasets but always the data assistant is suggesting only this expectation:  
expect\_column\_values\_to\_be\_null  
No matter dataset size, columns…always that. I would expect Data Assistant would suggest a lot of different expectations… This is the code used:

df = spark.table(“my\_dataset\_table”)  
context.add\_or\_update\_expectation\_suite(“my\_expectation\_suite”)  
validator = context.get\_validator(  
batch\_request=my\_batch\_request,  
expectation\_suite\_name=“my\_expectation\_suite”,  
)  
data\_assistant\_result = context.assistants.missingness.run(  
validator=validator,  
estimation=“flag\_outliers”  
)  
data\_assistant\_result.plot\_expectations\_and\_metrics()

---

<div class="post-metadata">

**Author:** ![ToivoMattila](https://yyz1.discourse-cdn.com/flex031/user_avatar/discourse.greatexpectations.io/toivomattila/32/254_2.png) [@ToivoMattila](https://discourse.greatexpectations.io/u/ToivoMattila)\
**Post date:** [April 20, 2024, 3:42pm UTC](https://discourse.greatexpectations.io/t/data-assistant-always-suggesting-only-one-expectation/1717/2 "2024-04-20T15:42:01Z")

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The `context.assistants.missingness` is the Missingess Data Assistant, which only checks for missing values (nulls) in your data and creates Expectations related to that.

You can try the Onboarding Data Assistant with `context.assistants.onboarding` which generates a wider range of Expectations.

There’s also the Volume Data Assistant (`context.assistants.volume`) which creates Expectations for row count and the number of distinct values in a column.

I couldn’t find documentation for the Onboarding or Volume Data Assistants but they work the same way as the Missingness Assistant