Evaluating whether your proposed ML use case is technically feasible given your current data, and whether ML is the right approach at all. We start by defining the problem formulation precisely: is this a classification task (binary or multi-class), a regression problem, an anomaly detection use case, or an NLP or computer vision problem? The formulation determines the data requirements, the evaluation metric, and the expected accuracy range. A binary classification problem requires a different label distribution, baseline model, and success metric than a multi-class or sequence labelling problem, getting this wrong at the start leads to a model that is evaluated against the wrong target. Baseline model test: before recommending a full build, we train a simple baseline using scikit-learn (logistic regression, decision tree, or a gradient boosting model via XGBoost or LightGBM depending on the data type) on a sample of your actual data. A baseline that fails to beat a naive majority-class predictor on your sample disproves the feasibility assumption in hours rather than weeks. Cross-validation strategy for the baseline depends on the data structure: stratified k-fold for classification with class imbalance, time-series split for sequential data where future leakage would inflate baseline accuracy, and group k-fold where data groups (customer IDs, session IDs) must not appear in both train and validation splits. Evaluation metric selection: for imbalanced classification, accuracy is misleading, we evaluate precision, recall, F1, and AUC-ROC to characterise model behaviour across the operating range rather than at a single threshold. Hyperparameter tuning for baseline models uses Optuna with a study budget of 50-100 trials, enough to establish whether the problem is learnable without spending days on exhaustive search. Most assessments find either that a rule-based or threshold-based system handles 80% of the use case at a fraction of the cost, or that the data volume and labelling quality are too low to support reliable predictions. Both findings are more valuable than a confident recommendation that turns out to be wrong.