# Grouped PSIS-LOO Influence

Pointwise PSIS-LOO diagnostics may be aggregated by a declared participant, item, condition, or other observation-level grouping variable.

    group_loo <- loo_group_influence_table(
      loo_atlas,
      group = "participant_id"
    )

    plot_loo_group_influence(group_loo)
    plot_loo_group_elpd(group_loo)

Aggregation supports review of concentrated predictive influence. It never removes a group automatically.