diff --git a/hlink/linking/model_exploration/link_step_train_test_models.py b/hlink/linking/model_exploration/link_step_train_test_models.py
index a7c79ec..8e391b8 100644
--- a/hlink/linking/model_exploration/link_step_train_test_models.py
+++ b/hlink/linking/model_exploration/link_step_train_test_models.py
@@ -4,11 +4,16 @@
 #   https://github.com/ipums/hlink
 
 import itertools
+import logging
 import math
 import re
+from time import perf_counter
+from typing import Any
 import numpy as np
 import pandas as pd
 from sklearn.metrics import precision_recall_curve, auc
+from pyspark.ml import Model, Transformer
+import pyspark.sql
 from pyspark.sql.functions import count, mean
 
 import hlink.linking.core.threshold as threshold_core
@@ -16,9 +21,11 @@
 
 from hlink.linking.link_step import LinkStep
 
+logger = logging.getLogger(__name__)
+
 
 class LinkStepTrainTestModels(LinkStep):
-    def __init__(self, task):
+    def __init__(self, task) -> None:
         super().__init__(
             task,
             "train test models",
@@ -35,7 +42,7 @@ def __init__(self, task):
             ],
         )
 
-    def _run(self):
+    def _run(self) -> None:
         training_conf = str(self.task.training_conf)
         table_prefix = self.task.table_prefix
         config = self.task.link_run.config
@@ -61,7 +68,15 @@ def _run(self):
         splits = self._get_splits(prepped_data, id_a, n_training_iterations, seed)
 
         model_parameters = self._get_model_parameters(config)
-        for run in model_parameters:
+
+        logger.info(
+            f"There are {len(model_parameters)} sets of model parameters to explore; "
+            f"each of these has {n_training_iterations} train-test splits to test on"
+        )
+        for run_index, run in enumerate(model_parameters, 1):
+            run_start_info = f"Starting run {run_index} of {len(model_parameters)} with these parameters: {run}"
+            print(run_start_info)
+            logger.info(run_start_info)
             params = run.copy()
             model_type = params.pop("type")
 
@@ -80,12 +95,17 @@ def _run(self):
                 threshold_ratio = False
 
             threshold_matrix = _calc_threshold_matrix(alpha_threshold, threshold_ratio)
-            results_dfs = {}
+            logger.debug(f"The threshold matrix has {len(threshold_matrix)} entries")
+
+            results_dfs: dict[int, pd.DataFrame] = {}
             for i in range(len(threshold_matrix)):
                 results_dfs[i] = _create_results_df()
 
             first = True
-            for training_data, test_data in splits:
+            for split_index, (training_data, test_data) in enumerate(splits, 1):
+                split_start_info = f"Training and testing the model on train-test split {split_index} of {n_training_iterations}"
+                print(split_start_info)
+                logger.debug(split_start_info)
                 training_data.cache()
                 test_data.cache()
 
@@ -93,7 +113,13 @@ def _run(self):
                     model_type, params, dep_var
                 )
 
+                logger.debug("Training the model on the training data split")
+                start_train_time = perf_counter()
                 model = classifier.fit(training_data)
+                end_train_time = perf_counter()
+                logger.debug(
+                    f"Successfully trained the model in {end_train_time - start_train_time:.2f}s"
+                )
 
                 predictions_tmp = _get_probability_and_select_pred_columns(
                     test_data, model, post_transformer, id_a, id_b, dep_var
@@ -113,7 +139,7 @@ def _run(self):
                 param_text = np.full(precision.shape, f"{model_type}_{params}")
 
                 pr_auc = auc(recall, precision)
-                print(f"Area under PR curve: {pr_auc}")
+                print(f"The area under the precision-recall curve is {pr_auc}")
 
                 if first:
                     prc = pd.DataFrame(
@@ -134,18 +160,24 @@ def _run(self):
                     first = False
 
                 i = 0
-                for at, tr in threshold_matrix:
+                for threshold_index, (alpha_threshold, threshold_ratio) in enumerate(
+                    threshold_matrix, 1
+                ):
+                    logger.debug(
+                        f"Predicting with threshold matrix entry {threshold_index} of {len(threshold_matrix)}: "
+                        f"{alpha_threshold=} and {threshold_ratio=}"
+                    )
                     predictions = threshold_core.predict_using_thresholds(
                         predictions_tmp,
-                        at,
-                        tr,
+                        alpha_threshold,
+                        threshold_ratio,
                         config[training_conf],
                         config["id_column"],
                     )
                     predict_train = threshold_core.predict_using_thresholds(
                         predict_train_tmp,
-                        at,
-                        tr,
+                        alpha_threshold,
+                        threshold_ratio,
                         config[training_conf],
                         config["id_column"],
                     )
@@ -157,8 +189,8 @@ def _run(self):
                         model,
                         results_dfs[i],
                         otd_data,
-                        at,
-                        tr,
+                        alpha_threshold,
+                        threshold_ratio,
                         pr_auc,
                     )
                     i += 1
@@ -175,7 +207,19 @@ def _run(self):
         self._save_otd_data(otd_data, self.task.spark)
         self.task.spark.sql("set spark.sql.shuffle.partitions=200")
 
-    def _get_splits(self, prepped_data, id_a, n_training_iterations, seed):
+    def _get_splits(
+        self,
+        prepped_data: pyspark.sql.DataFrame,
+        id_a: str,
+        n_training_iterations: int,
+        seed: int,
+    ) -> list[list[pyspark.sql.DataFrame]]:
+        """
+        Get a list of random splits of the prepped_data into two DataFrames.
+        There are n_training_iterations elements in the list. Each element is
+        itself a list of two DataFrames which are the splits of prepped_data.
+        The split DataFrames are roughly equal in size.
+        """
         if self.task.link_run.config[f"{self.task.training_conf}"].get(
             "split_by_id_a", False
         ):
@@ -200,7 +244,7 @@ def _get_splits(self, prepped_data, id_a, n_training_iterations, seed):
 
         return splits
 
-    def _custom_param_grid_builder(self, conf):
+    def _custom_param_grid_builder(self, conf: dict[str, Any]) -> list[dict[str, Any]]:
         print("Building param grid for models")
         given_parameters = conf[f"{self.task.training_conf}"]["model_parameters"]
         new_params = []
@@ -231,19 +275,18 @@ def _custom_param_grid_builder(self, conf):
 
     def _capture_results(
         self,
-        predictions,
-        predict_train,
-        dep_var,
-        model,
-        results_df,
-        otd_data,
-        at,
-        tr,
-        pr_auc,
-    ):
+        predictions: pyspark.sql.DataFrame,
+        predict_train: pyspark.sql.DataFrame,
+        dep_var: str,
+        model: Model,
+        results_df: pd.DataFrame,
+        otd_data: dict[str, Any] | None,
+        alpha_threshold: float,
+        threshold_ratio: float,
+        pr_auc: float,
+    ) -> pd.DataFrame:
         table_prefix = self.task.table_prefix
 
-        print("Evaluating model performance...")
         # write to sql tables for testing
         predictions.createOrReplaceTempView(f"{table_prefix}predictions")
         predict_train.createOrReplaceTempView(f"{table_prefix}predict_train")
@@ -278,13 +321,13 @@ def _capture_results(
                 "test_mcc": [test_mcc],
                 "train_mcc": [train_mcc],
                 "model_id": [model],
-                "alpha_threshold": [at],
-                "threshold_ratio": [tr],
+                "alpha_threshold": [alpha_threshold],
+                "threshold_ratio": [threshold_ratio],
             },
         )
         return pd.concat([results_df, new_results], ignore_index=True)
 
-    def _get_model_parameters(self, conf):
+    def _get_model_parameters(self, conf: dict[str, Any]) -> list[dict[str, Any]]:
         training_conf = str(self.task.training_conf)
 
         model_parameters = conf[training_conf]["model_parameters"]
@@ -296,7 +339,9 @@ def _get_model_parameters(self, conf):
             )
         return model_parameters
 
-    def _save_training_results(self, desc_df, spark):
+    def _save_training_results(
+        self, desc_df: pd.DataFrame, spark: pyspark.sql.SparkSession
+    ) -> None:
         table_prefix = self.task.table_prefix
 
         if desc_df.empty:
@@ -310,7 +355,9 @@ def _save_training_results(self, desc_df, spark):
                 f"Training results saved to Spark table '{table_prefix}training_results'."
             )
 
-    def _prepare_otd_table(self, spark, df, id_a, id_b):
+    def _prepare_otd_table(
+        self, spark: pyspark.sql.SparkSession, df: pd.DataFrame, id_a: str, id_b: str
+    ) -> pyspark.sql.DataFrame:
         spark_df = spark.createDataFrame(df)
         counted = (
             spark_df.groupby(id_a, id_b)
@@ -323,7 +370,9 @@ def _prepare_otd_table(self, spark, df, id_a, id_b):
         )
         return counted
 
-    def _save_otd_data(self, otd_data, spark):
+    def _save_otd_data(
+        self, otd_data: dict[str, Any] | None, spark: pyspark.sql.SparkSession
+    ) -> None:
         table_prefix = self.task.table_prefix
 
         if otd_data is None:
@@ -379,7 +428,7 @@ def _save_otd_data(self, otd_data, spark):
         else:
             print("There were no true negatives recorded.")
 
-    def _create_otd_data(self, id_a, id_b):
+    def _create_otd_data(self, id_a: str, id_b: str) -> dict[str, Any] | None:
         """Output Suspicous Data (OTD): used to check config to see if you should find sketchy training data that the models routinely mis-classify"""
         training_conf = str(self.task.training_conf)
         config = self.task.link_run.config
@@ -400,7 +449,12 @@ def _create_otd_data(self, id_a, id_b):
             return None
 
 
-def _calc_mcc(TP, TN, FP, FN):
+def _calc_mcc(TP: int, TN: int, FP: int, FN: int) -> float:
+    """
+    Given the counts of true positives (TP), true negatives (TN), false
+    positives (FP), and false negatives (FN) for a model run, compute the
+    Matthews Correlation Coefficient (MCC).
+    """
     if (math.sqrt((TP + FP) * (TP + FN) * (TN + FP) * (TN + FN))) != 0:
         mcc = ((TP * TN) - (FP * FN)) / (
             math.sqrt((TP + FP) * (TP + FN) * (TN + FP) * (TN + FN))
@@ -410,7 +464,9 @@ def _calc_mcc(TP, TN, FP, FN):
     return mcc
 
 
-def _calc_threshold_matrix(alpha_threshold, threshold_ratio):
+def _calc_threshold_matrix(
+    alpha_threshold: float | list[float], threshold_ratio: float | list[float]
+) -> list[list[float]]:
     if alpha_threshold and type(alpha_threshold) != list:
         alpha_threshold = [alpha_threshold]
 
@@ -426,8 +482,13 @@ def _calc_threshold_matrix(alpha_threshold, threshold_ratio):
 
 
 def _get_probability_and_select_pred_columns(
-    pred_df, model, post_transformer, id_a, id_b, dep_var
-):
+    pred_df: pyspark.sql.DataFrame,
+    model: Model,
+    post_transformer: Transformer,
+    id_a: str,
+    id_b: str,
+    dep_var: str,
+) -> pyspark.sql.DataFrame:
     all_prediction_cols = set(
         [
             f"{id_a}",
@@ -446,7 +507,9 @@ def _get_probability_and_select_pred_columns(
     return required_col_df
 
 
-def _get_confusion_matrix(predictions, dep_var, otd_data):
+def _get_confusion_matrix(
+    predictions: pyspark.sql.DataFrame, dep_var: str, otd_data: dict[str, Any] | None
+) -> tuple[int, int, int, int]:
     TP = predictions.filter((predictions[dep_var] == 1) & (predictions.prediction == 1))
     TP_count = TP.count()
 
@@ -486,7 +549,16 @@ def _get_confusion_matrix(predictions, dep_var, otd_data):
     return TP_count, FP_count, FN_count, TN_count
 
 
-def _get_aggregate_metrics(TP_count, FP_count, FN_count, TN_count):
+def _get_aggregate_metrics(
+    TP_count: int, FP_count: int, FN_count: int, TN_count: int
+) -> tuple[float, float, float]:
+    """
+    Given the counts of true positives, false positivies, false negatives, and
+    true negatives for a model run, compute several metrics to evaluate the
+    model's quality.
+
+    Return a tuple of (precision, recall, Matthews Correlation Coefficient).
+    """
     if (TP_count + FP_count) == 0:
         precision = np.nan
     else:
@@ -499,7 +571,7 @@ def _get_aggregate_metrics(TP_count, FP_count, FN_count, TN_count):
     return precision, recall, mcc
 
 
-def _create_results_df():
+def _create_results_df() -> pd.DataFrame:
     return pd.DataFrame(
         columns=[
             "precision_test",
@@ -516,7 +588,12 @@ def _create_results_df():
     )
 
 
-def _append_results(desc_df, results_df, model_type, params):
+def _append_results(
+    desc_df: pd.DataFrame,
+    results_df: pd.DataFrame,
+    model_type: str,
+    params: dict[str, Any],
+) -> pd.DataFrame:
     # run.pop("type")
     print(results_df)
 
@@ -548,7 +625,7 @@ def _append_results(desc_df, results_df, model_type, params):
     return desc_df
 
 
-def _print_desc_df(desc_df):
+def _print_desc_df(desc_df: pd.DataFrame) -> None:
     pd.set_option("display.max_colwidth", None)
     print(
         desc_df.drop(
@@ -564,7 +641,7 @@ def _print_desc_df(desc_df):
     print("\n")
 
 
-def _load_desc_df_params(desc_df):
+def _load_desc_df_params(desc_df: pd.DataFrame) -> pd.DataFrame:
     params = [
         "maxDepth",
         "numTrees",
@@ -591,7 +668,7 @@ def _load_desc_df_params(desc_df):
     return desc_df
 
 
-def _create_desc_df():
+def _create_desc_df() -> pd.DataFrame:
     return pd.DataFrame(
         columns=[
             "model",