Count One to Many Relationship

hi, luisc 

This is a measure totals problem. Very common. See this post about it
https://community.powerbi.com/t5/DAX-Commands-and-Tips/Dealing-with-Measure-Totals/td-p/63376

Also, this Quick Measure, Measure Totals, The Final Word should get you what you need:
https://community.powerbi.com/t5/Quick-Measures-Gallery/Measure-Totals-The-Final-Word/m-p/547907

For your case, when you count of id_pessoa (pessoa table) , It likes a measure as below:

Measure = CALCULATE(COUNTA(pessoa[id_pessoa]))

and when you count of person_id (scoring table), it likes a measure as below:

Measure 2 = CALCULATE(COUNTA(scoring[person_id]))

So for your case, just try to use this formula to create a measure

Output = var _table=ADDCOLUMNS(scoring,"_id_pessod",RELATED(pessoa[id_pessoa])) return
COUNTAX(_table,[_id_pessod])

Result:

for example:

and here is my sample pbix file, please try it.

 

Regards,

Lin