The two sources for collecting information are primary and secondary. After gathering information, interpretation and validation help to complete the data. The purpose of assessment is to establish data with the initial information, to interpret data about the patient's perceived needs and health problems, and to respond to these problems identified.

The nurse collects all aspects of the patient's health in the initial assessment, establishing priorities for ongoing focused assessments and creating a reference for future comparison. Most institutions have policies specifying the time interval in completing the initial assessment. The nurse approaches the patient, considering the patient's culture, for example, whether or not one makes direct eye contact or shakes a hand.

In a focused assessment, the nurse gathers data about a specific problem. The focused assessment can also be done during the initial assessment if the patient's primary health problem surfaces, but it is routinely part of ongoing data collection.

When a physiological or psychological crisis presents itself, the nurse performs an emergency assessment to identify life-threatening problems. For example, an elderly resident who begins choking in the dining room, an unresponsive patient in the rehabilitation unit, and a factory worker threatening violence are all candidates for an emergency assessment.

Time-lapsed assessment is the reassessment of the patient's current health status. It helps to compare the patient's current status to baseline data obtained earlier. Most patients receiving nursing care over longer periods, such as homebound patients with visiting nurses, are scheduled for periodic time-lapsed assessments to reassess health status and make necessary revisions in the care plan.

Establishing assessment priorities and systematically structuring data collection are two important considerations when preparing for data collection. After completing the comprehensive nursing assessment, patient health problems dictate assessment priorities for future nurse-patient interactions.