#hope-s [[HOPES Project Index]] [[20211120 All about EMA and EMI]] 202201271526 How to design EMA? #EMA ## How to design EMA? EMA can be divided into event-based sampling and time-based sampling schemes. ### Event-Based Sampling [[Ecological Momentary Assessment. Saul Shiffman, Arthur A. Stone, and Michael R. Hufford#^40d433]] It could be instances of a relapse of drinking, violence, panic attacks. It is user defined. User determine if that event has occurred Recording of events can show frequency and time distribution. User can press a button to log to start recording (other data such as duration, intensity, antecedent mood etc). There is no way to verify/assess compliance. Subject to poor compliance of falsification ### Time-Based Sampling [[Ecological Momentary Assessment. Saul Shiffman, Arthur A. Stone, and Michael R. Hufford#^61b581]] Used to monitor clinical phenomena such as pain, mood, which varied continuously. The frequency of time-based assessments is dependent on resolution the study needed. The intervals could be fixed intervals - common for blood pressure monitoring, or varied intervals. Will have to consider the subject burdens in responding to EMAs.  Should be during waking day, 10-10pm etc **A point to have random timing sampling** Reference: [[ClinTouch - The feasibility and validity of ambulatory self report of psychotic symptoms using a smartphone software application]] "A pseudo-random, as opposed to fixed, sampling schedule was thought to be advantageous since it facilitated the assessment of a wide range of situations and times of the day and prevented individuals from greatly changing their activities in order to account for completing the questions [23]. Forced entry times were also expected to reduce response bias (e.g only completing the diary when asymptomatic)" ^1a9788 ### Combination Sampling Design [[Ecological Momentary Assessment. Saul Shiffman, Arthur A. Stone, and Michael R. Hufford#^49a069]] Depending on the nature of the study, time and event based design can be combined. Such as panic attacks (Margraf et al. 1987), binge eating episodes Engel et al. 2007 -- does negative affect come before binge eating?, Smoking cessation, Pain relief after taking medicine, Drinking habits. Some studies also include some degree of retrospection. Thus researcher must consider the biases even for a short interval. Even though we may have assessed their mood 12 times in a day, and found them happy each time, it is possible that they experienced moments of misery in between the assessments.  Combine objective (passive data) to compliment active EMA to cover the whole day. [[Ecological Momentary Assessment. Saul Shiffman, Arthur A. Stone, and Michael R. Hufford#^bf81e9]] Methodology Consideration [[20211120 All about EMA and EMI#^e1a9af]] [[202201271457 EMI need to link with a human support]]