Table: it 's always sunny in philadelphia (season 6)
Question: Do the episodes directed by Matt Shakman have higher or lower viewership ratings compared to those directed by Randall Einhorn? Answer with only 'higher' or 'lower' that is most accurate and nothing else.
Step 1 (Operation, Grouping): directed by
Step 2 (Operation, Indexing): us viewers (million)
Step 3 (Reasoning, Aggregating): AVG, us viewers (million)
Step 4 (Reasoning, Arithmetic): comparison, average points
Answer: lower