diff --git a/pygem/plot/graphics.py b/pygem/plot/graphics.py
index 7194dc6a..b70d4a31 100644
--- a/pygem/plot/graphics.py
+++ b/pygem/plot/graphics.py
@@ -274,12 +274,12 @@ def plot_mcmc_chain(
             continue
 
         # stack predictions first (shape: n_steps x ... x ...) - may end up being 2d or 3d
-        pred_primes = torch.stack(pred_primes[key]).numpy()
-        pred_chain = torch.stack(pred_chain[key]).numpy()
+        pred_primes_key = torch.stack(pred_primes[key]).numpy()
+        pred_chain_key = torch.stack(pred_chain[key]).numpy()
 
         # flatten all axes except the first (n_steps) -> 2D array (n_steps, M)
-        pred_primes_flat = pred_primes.reshape(pred_primes.shape[0], -1)
-        pred_chain_flat = pred_chain.reshape(pred_chain.shape[0], -1)
+        pred_primes_flat = pred_primes_key.reshape(pred_primes_key.shape[0], -1)
+        pred_chain_flat = pred_chain_key.reshape(pred_chain_key.shape[0], -1)
 
         # make obs array broadcastable (flatten if needed)
         obs_vals_flat = np.ravel(np.array(obs[key][0]))
@@ -291,6 +291,9 @@ def plot_mcmc_chain(
         axes[nparams].plot(mean_resid_primes, '.', ms=ms, c='tab:blue')
         axes[nparams].plot(mean_resid_chain, '.', ms=ms, c='tab:orange')
 
+        axes[nparams].text(
+            0.02, 0.02, key, transform=axes[nparams].transAxes, fontsize=fontsize, va='bottom', ha='left'
+        )
         if key == 'elev_change_1d':
             axes[nparams].set_ylabel(r'$\overline{\hat{dh} - dh}$', fontsize=fontsize)
         else: