## 3 Methodology
### Data Collection Instruments  
To empirically assess the relationship between omnichannel service components and customer satisfaction, two structured self-administered questionnaires were developed. Both instruments employed a five-point Likert scale, ranging from 1 = Strongly Disagree to 5 = Strongly Agree, allowing respondents to express their level of agreement with each item in a standardized format.  
The first instrument was designed to measure the perceived quality and functionality of the omnichannel service experience. It comprised 12 items grouped into three conceptual dimensions derived from the model proposed by the Asociacion Mexicana de Venta Online [10] and aligned with the academic literature on digital service systems [3; 12; 32]. These dimensions included the following:  
1. Data integration (4 items): These items measured whether the customer perceived the product and service information as clear, centralized, and updated across digital and physical channels. This included visibility of the stock, personalized content, and consistent communication.
2. Digital payment systems (6 items): These items assessed the availability and ease of various payment methods, such as mobile wallets, online card payments, and cash options synchronized with digital orders.
3. Logistics flexibility (2 items): Questions evaluated the extent to which users could choose between home delivery and in-store pickup, as well as whether logistical processes were perceived as reliable and timely.  
The second instrument focused on measuring customer satisfaction, operationalized in line with the expectancy-disconfirmation paradigm (EDP) [8; 27]. It included 8 items structured around two key dimensions that are also central to QoE assessments:  
1. Customer expectations (2 items): These items explored whether customers felt their expectations about the service were met or exceeded.
2. Perceived value (6 items): Items in this category captured how customers assessed the benefits received in relation to the time, effort, and costs incurred. This included perceptions of fair pricing, efficient service, and emotional satisfaction.  
The complete list of items for both instruments can be found in Appendix A. The instruments were administered in Spanish, the participants' native language, and carefully translated to preserve conceptual integrity. The survey required approximately 10 to 12 min to complete. Participants filled out the questionnaires in a quiet area near the service facility, with a researcher available to clarify questions without influencing the responses. The development of both instruments was grounded in validated theoretical constructs and designed for applicability in low-to-medium digital literacy contexts, where simplicity and clarity are essential. The goal was to capture perceived experience rather than technical accuracy, reflecting the subjective nature of both satisfaction and Quality of Experience (QoE). While the instruments were designed to capture key perceptual indicators with clarity and simplicity, we acknowledge that the limited number of items per dimension and the exclusive reliance on self-reported data constrain the analytical depth of the study. The absence of behavioral data (e.g., app usage logs) or qualitative follow-up limits the ability to triangulate perceptions with objective service-use patterns.