Counting total records vs status

I'm looking to do an update for a batch when all the jobs for that batch are completed. To do this I want to compare the total number of jobs vs the total completed. I'm doing that with the query below, however it's a pretty slow query. Any suggestions to improve this? Or alternate ways to approach the main update?

SELECT DISTINCT j.BatchId, 
    j.JobStatusId,
    COUNT(j.BatchId) OVER(PARTITION BY j.BatchID, j.JobStatusID),
    COUNT(j.BatchId) OVER(PARTITION BY j.BatchID) 
FROM [Job] j 
ORDER BY j.BatchID