| [Background] Smart phone APP,as an important part of m Health,is drawing more attention from medical researchers.To improve the status of immunization coverage of children in rural Sichuan Province,EPI APP,a smart phone APP,has been developed by Save the Children China Program and will be piloted in Xuanhan County,Dazhou City.The effectiveness of EPI APP will be evaluated by a cluster randomized controlled trial.The target users of the APP are village doctors who manage child immunization in their catchment areas.The main functions of EPI APP include making appointments,recording immunization information,tracking children not receiving timely immunization,and providing health education information for village doctors.Currently,mHealth APP developers have mainly focused their research on evaluating APP's health effectiveness with few researchers on design problems or potential usability errors.Researches indicate that it is imperative to identify and correct design problems before an APP is used.An effective method for early detecting of design errors is heuristic evaluation combined with a usability and feasibility test.[Objectives]To identify and correct errors of the EPI APP and improve its usability by conducting heuristic evaluation,usability test and feasibility test before being used by village doctors in a randomized controlled trial.[Methods] This study was divided into three phases: the heuristic evaluation,the usability test and the feasibility test.Researchers led an adaptation workshop and two rounds of expert revision to determine 63 items with eight principles in the heuristic evaluation.In the heuristic evaluation,we first asked experts to perform nine use cases covering all APP functions to familiarize them with EPI APP and then score violation of the eight heuristic evaluation principles based on a 5-point scale(0=no usability problem to 4=usability catastrophe).Violations were defined as problems that could potentially interfere with the end users(village doctors)using the app effectively.In the usability test,we prepared the same nine use cases to assess the performance of village doctors,recording how long it took to complete the tasks,completion rate for each use case,and the number of errors or confusions end users confronted.Users' perception of ease of use and usefulness(PEUU)scale was determined with a seven-point Likert-type scale(1=extremely disagree to 7=extremely agree).We encouraged all the experts and village doctors to ?think out loud? to give their comments on how to improve EPI App.In the feasibility test,we collected information about the degree of village doctors' satisfaction towards EPI APP by conducting twice semi-structured interview.[Results] Three experts identified 40 violations against the eight heuristic principles.The frequencies for each heuristic principle suggested that the improvements of EPI APP needed to focus on visibility and match between the system and the real world.The average severity ratings ranged from 0.4to 1.8(0=no usability problem to 4=usability catastrophe),which indicated minor usability problems,not requiring an immediate fix.In usability test,the mean time spent by village doctors on each use case varied from 3.8 seconds to 162.1 seconds while the completion rate varied from 0 to 2.7.Village doctors considered EPI APP useful and easy to use.In the two rounds of feasibility test,most of the doctors were satisfied with EPI APP and would like to complete their works with EPI APP in the future.Based on the comments of expert and village doctors and the feasibility of revision,we made 21 modifications to the EPI APP.[Conclusions] Heuristic evaluation conducted combined with the usability test and feasibility test could provide advice on EPI APP improvement from complementary perspectives,which contributes to a more user-friendly design and usability. |
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