diff --git a/ivmodels/tests/anderson_rubin.py b/ivmodels/tests/anderson_rubin.py
index 43e2c95..d2091de 100644
--- a/ivmodels/tests/anderson_rubin.py
+++ b/ivmodels/tests/anderson_rubin.py
@@ -132,7 +132,7 @@ def anderson_rubin_test(
         Regressors.
     y: np.ndarray of dimension (n,)
         Outcomes.
-    beta: np.ndarray of dimension (mx,)
+    beta: np.ndarray of dimension (mx + md,)
         Coefficients to test.
     W: np.ndarray of dimension (n, mw) or None, optional, default = None
         Endogenous regressors not of interest.
diff --git a/ivmodels/tests/conditional_likelihood_ratio.py b/ivmodels/tests/conditional_likelihood_ratio.py
index 1346051..b1f4fe6 100644
--- a/ivmodels/tests/conditional_likelihood_ratio.py
+++ b/ivmodels/tests/conditional_likelihood_ratio.py
@@ -277,11 +277,11 @@ def conditional_likelihood_ratio_test(
     ----------
     Z: np.ndarray of dimension (n, k)
         Instruments.
-    X: np.ndarray of dimension (n, mx + md)
+    X: np.ndarray of dimension (n, mx)
         Regressors.
     y: np.ndarray of dimension (n,)
         Outcomes.
-    beta: np.ndarray of dimension (mx,)
+    beta: np.ndarray of dimension (mx + md,)
         Coefficients to test.
     W: np.ndarray of dimension (n, mw) or None, optional, default = None
         Endogenous regressors not of interest.
diff --git a/ivmodels/tests/likelihood_ratio.py b/ivmodels/tests/likelihood_ratio.py
index 91dcd88..de12c47 100644
--- a/ivmodels/tests/likelihood_ratio.py
+++ b/ivmodels/tests/likelihood_ratio.py
@@ -46,7 +46,7 @@ def likelihood_ratio_test(Z, X, y, beta, W=None, C=None, D=None, fit_intercept=T
         Regressors.
     y: np.ndarray of dimension (n,)
         Outcomes.
-    beta: np.ndarray of dimension (mx,)
+    beta: np.ndarray of dimension (mx + md,)
         Coefficients to test.
     W: np.ndarray of dimension (n, mw) or None, optional, default=None
         Endogenous regressors not of interest.
diff --git a/ivmodels/tests/pulse.py b/ivmodels/tests/pulse.py
index 3c685db..193ff1f 100644
--- a/ivmodels/tests/pulse.py
+++ b/ivmodels/tests/pulse.py
@@ -25,7 +25,7 @@ def pulse_test(Z, X, y, beta, C=None, W=None, D=None, fit_intercept=True):
         Regressors.
     y: np.ndarray of dimension (n,)
         Outcomes.
-    beta: np.ndarray of dimension (mx,)
+    beta: np.ndarray of dimension (mx + md,)
         Coefficients to test.
     C: np.ndarray of dimension (n, mc) or None, optional, default=None
         Exogenous regressors not of interest.
diff --git a/ivmodels/tests/utils.py b/ivmodels/tests/utils.py
index a887469..7989606 100644
--- a/ivmodels/tests/utils.py
+++ b/ivmodels/tests/utils.py
@@ -19,7 +19,7 @@ def _check_test_inputs(Z, X, y, W=None, C=None, D=None, beta=None):
         Exogenous regressors not of interest.
     D: np.ndarray of dimension (n, md), optional, default=None
         Exogenous regressors of interest.
-    beta: np.ndarray of dimension (mx,), optional, default=None
+    beta: np.ndarray of dimension (mx + md,), optional, default=None
         Coefficients.
 
     Returns
diff --git a/ivmodels/tests/wald.py b/ivmodels/tests/wald.py
index 31b9728..553a938 100644
--- a/ivmodels/tests/wald.py
+++ b/ivmodels/tests/wald.py
@@ -51,7 +51,7 @@ def wald_test(
         Exogenous regressors not of interest.
     D: np.ndarray of dimension (n, md) or None
         Exogenous regressors of interest.
-    beta: np.ndarray of dimension (mx,)
+    beta: np.ndarray of dimension (mx + md,)
         Coefficients to test.
     estimator: str or float, optional, default = "liml"
         Estimator to use. Passed to ``kappa`` argument of ``KClass``.