Training & optimisation
A setting a person chooses before model training starts, such as step size or number of rounds, and that the model does not learn itself.
Formal
A value that shapes how model training runs or how large the model is, fixed from outside rather than learned from the training data; it is tuned by trying values and comparing results on a validation set.
In plain English
Like the oven heat and baking time you set before the cake goes in; the cake does not choose them, but they decide how it turns out.
In practice
A data analyst in a municipality runs twenty short training jobs overnight on a model that forecasts demand for home care, each with a different step size and batch size, and keeps the combination that does best on held-back cases.
Why it matters
The same model and data can give a strong or a useless result depending on these settings, and searching them multiplies the cost of training.