* Data Collection is Essential: The scientific method relies on gathering evidence to support or refute a hypothesis. This evidence comes from data collection, whether it's through observations, measurements, experiments, or surveys.

* Controlled Experiments are Optional: While controlled experiments are a powerful tool in science, they are not always necessary. Observational studies and other forms of data collection can be equally valuable in certain fields.

In summary, data collection is a fundamental step in the scientific method, whereas controlled experiments are a specific technique used to gather data in certain situations.