diff --git a/python/ray/tune/suggest/ax.py b/python/ray/tune/suggest/ax.py
index 6e5cd3cdd..8cc6949ff 100644
--- a/python/ray/tune/suggest/ax.py
+++ b/python/ray/tune/suggest/ax.py
@@ -42,7 +42,7 @@ class AxSearch(Searcher):
             (list of two values, lower bound first), "values" for choice
             parameters (list of values), and "value" for fixed parameters
             (single value).
-        objective_name (str): Name of the metric used as objective in this
+        metric (str): Name of the metric used as objective in this
             experiment. This metric must be present in `raw_data` argument
             to `log_data`. This metric must also be present in the dict
             reported/returned by the Trainable.
@@ -53,7 +53,7 @@ class AxSearch(Searcher):
         outcome_constraints (list[str]): Outcome constraints of form
             "metric_name >= bound", like "m1 <= 3."
         ax_client (AxClient): Optional AxClient instance. If this is set, do
-            not pass any values to these parameters: `space`, `objective_name`,
+            not pass any values to these parameters: `space`, `metric`,
             `parameter_constraints`, `outcome_constraints`.
         use_early_stopped_trials: Deprecated.
         max_concurrent (int): Deprecated.
@@ -75,7 +75,7 @@ class AxSearch(Searcher):
                 intermediate_result = config["x1"] + config["x2"] * i
                 tune.report(score=intermediate_result)
 
-        ax_search = AxSearch(objective_name="score")
+        ax_search = AxSearch(metric="score")
         tune.run(
             config=config,
             easy_objective,
@@ -99,7 +99,7 @@ class AxSearch(Searcher):
                 intermediate_result = config["x1"] + config["x2"] * i
                 tune.report(score=intermediate_result)
 
-        ax_search = AxSearch(space=parameters, objective_name="score")
+        ax_search = AxSearch(space=parameters, metric="score")
         tune.run(easy_objective, search_alg=ax_search)
 
     """
@@ -113,7 +113,9 @@ class AxSearch(Searcher):
                  ax_client: Optional[AxClient] = None,
                  use_early_stopped_trials: Optional[bool] = None,
                  max_concurrent: Optional[int] = None):
-        assert ax is not None, "Ax must be installed!"
+        assert ax is not None, """Ax must be installed!
+            You can install AxSearch with the command:
+            `pip install ax-platform sqlalchemy`."""
         if mode:
             assert mode in ["min", "max"], "`mode` must be 'min' or 'max'."
 
diff --git a/python/ray/tune/suggest/bohb.py b/python/ray/tune/suggest/bohb.py
index 33f22640f..e5f371674 100644
--- a/python/ray/tune/suggest/bohb.py
+++ b/python/ray/tune/suggest/bohb.py
@@ -106,7 +106,9 @@ class TuneBOHB(Searcher):
                  mode: Optional[str] = None,
                  seed: Optional[int] = None):
         from hpbandster.optimizers.config_generators.bohb import BOHB
-        assert BOHB is not None, "HpBandSter must be installed!"
+        assert BOHB is not None, """HpBandSter must be installed!
+            You can install HpBandSter with the command:
+            `pip install hpbandster ConfigSpace`."""
         if mode:
             assert mode in ["min", "max"], "`mode` must be 'min' or 'max'."
         self._max_concurrent = max_concurrent
diff --git a/python/ray/tune/suggest/nevergrad.py b/python/ray/tune/suggest/nevergrad.py
index 75a399a6c..901ba4978 100644
--- a/python/ray/tune/suggest/nevergrad.py
+++ b/python/ray/tune/suggest/nevergrad.py
@@ -100,7 +100,9 @@ class NevergradSearch(Searcher):
                  mode: Optional[str] = None,
                  max_concurrent: Optional[int] = None,
                  **kwargs):
-        assert ng is not None, "Nevergrad must be installed!"
+        assert ng is not None, """Nevergrad must be installed!
+            You can install Nevergrad with the command:
+            `pip install nevergrad`."""
         if mode:
             assert mode in ["min", "max"], "`mode` must be 'min' or 'max'."
 
diff --git a/python/ray/tune/suggest/sigopt.py b/python/ray/tune/suggest/sigopt.py
index b3d0d2122..415e8aa3a 100644
--- a/python/ray/tune/suggest/sigopt.py
+++ b/python/ray/tune/suggest/sigopt.py
@@ -144,7 +144,9 @@ class SigOptSearch(Searcher):
         if connection is not None:
             self.conn = connection
         else:
-            assert sgo is not None, "SigOpt must be installed!"
+            assert sgo is not None, """SigOpt must be installed!
+                You can install SigOpt with the command:
+                `pip install -U sigopt`."""
             assert "SIGOPT_KEY" in os.environ, \
                 "SigOpt API key must be stored as " \
                 "environ variable at SIGOPT_KEY"