diff --git a/specs/core/1_shard-data-chains.md b/specs/core/1_shard-data-chains.md
index 2984b3fb7..af49825bd 100644
--- a/specs/core/1_shard-data-chains.md
+++ b/specs/core/1_shard-data-chains.md
@@ -89,7 +89,7 @@ def get_proposal_committee(seed: Bytes32,
     
     later_committee_start = epoch - (epoch % PROPOSAL_RESHUFFLE_PERIOD) - PROPOSAL_RESHUFFLE_PERIOD
     later_committee = split(shuffle(
-        get_active_validator_indices(validators, earlier_committee_start),
+        get_active_validator_indices(validators, later_committee_start),
         generate_seed(state, later_committee_start)
     ), SHARD_COUNT)[shard]