diff --git a/src/solution/methods/XavQiuWanThi2019/optimize.jl b/src/solution/methods/XavQiuWanThi2019/optimize.jl
index 57a202e..a96ff15 100644
--- a/src/solution/methods/XavQiuWanThi2019/optimize.jl
+++ b/src/solution/methods/XavQiuWanThi2019/optimize.jl
@@ -2,7 +2,9 @@
 # Copyright (C) 2020, UChicago Argonne, LLC. All rights reserved.
 # Released under the modified BSD license. See COPYING.md for more details.
 
-function optimize!(model::JuMP.Model, method::XavQiuWanThi2019.Method)::Nothing
+using DataStructures
+
+function optimize!(model::JuMP.Model, method::XavQiuWanThi2019.Method)::Dict
     if !occursin("Gurobi", JuMP.solver_name(model))
         method.two_phase_gap = false
     end
@@ -22,6 +24,9 @@ function optimize!(model::JuMP.Model, method::XavQiuWanThi2019.Method)::Nothing
             large_gap = true
         end
     end
+    stats = Dict(
+        "violations" => []
+    )
     while true
         time_elapsed = time() - initial_time
         time_remaining = method.time_limit - time_elapsed
@@ -68,6 +73,7 @@ function optimize!(model::JuMP.Model, method::XavQiuWanThi2019.Method)::Nothing
 
         if violations_found
             for (i, v) in enumerate(violations)
+                append!(stats["violations"], v)
                 _enforce_transmission(model, v, model[:instance].scenarios[i])
             end
         else
@@ -80,5 +86,5 @@ function optimize!(model::JuMP.Model, method::XavQiuWanThi2019.Method)::Nothing
             end
         end
     end
-    return
+    return stats
 end
diff --git a/src/solution/optimize.jl b/src/solution/optimize.jl
index 635e5e2..a105ce3 100644
--- a/src/solution/optimize.jl
+++ b/src/solution/optimize.jl
@@ -3,12 +3,12 @@
 # Released under the modified BSD license. See COPYING.md for more details.
 
 """
-    optimize!(model::JuMP.Model)::Nothing
+    optimize!(model::JuMP.Model)::Dict
 
 Solve the given unit commitment model. Unlike `JuMP.optimize!`, this uses more
 advanced methods to accelerate the solution process and to enforce transmission
 and N-1 security constraints.
 """
-function optimize!(model::JuMP.Model)::Nothing
+function optimize!(model::JuMP.Model)::Dict
     return UnitCommitment.optimize!(model, XavQiuWanThi2019.Method())
 end