Phase 1 focused on iterative, user-centered refinement of iGET Living. Across 3 cycles of user testing sessions, quantitative and qualitative data on treatment content, clarity, acceptability, layout, and overall engagement were collected. Each cycle informed real-time refinement of modules, navigation structure, and visual presentation.

Participants were recruited from the Pediatric Pain Management Clinic at Stanford Medicine, Children’s Health. To be eligible, youth (1) were between ages 10 and 18 years old, (2) had a diagnosis of chronic (>3 mo) pain, (3) were English literate, and (4) had access to a computer, smartphone, or tablet with internet connection. Review of the literature and previously conducted usability testing studies indicates that prototype refinement is typically achieved within 2‐3 cycles of testing, with ≈5 participants in each cycle [38,39]. Given this, we aimed to enroll 5 youth per interview cycle, with a total of 3 cycles, resulting in a final sample of 15 youth.

Eligible participants were provided a link to a secure web-based screening form via REDCap, where they left contact information and expressed interest in participation. A research assistant (RA) followed up with a phone call to confirm eligibility, and once confirmed, the RA scheduled a user development session. Consent, assent, and demographic information were obtained via REDCap prior to the user development session. User development sessions were 2 hours long and conducted via Zoom by an RA. During the development session, participants were given access to the digital prototype and were able to view content and pilot features. The development sessions also followed a semistructured interview guide containing Likert-rated and open-ended questions guided by the CFIR Intervention Characteristics domain [33]. Participants were also encouraged to think aloud about likes, dislikes, and difficulties with understanding the content or navigating the prototype. All user development sessions were audio-recorded and stored on a secure cloud-based platform. Data were collected following engagement with each module, as well as at the conclusion of viewing all the content in the prototype. Modules were refined based on quantitative ratings and qualitative data during a series of 3 iterative cycles.

Sample characteristics were examined using descriptive statistics. To facilitate intervention refinement, qualitative data from user development sessions were analyzed using rapid qualitative analysis [40]. Rapid qualitative analysis is a pragmatic and efficient approach to analyzing qualitative data, designed to deliver timely and actionable results. It is often used in intervention development, implementation science, or health services research and prioritizes speed and utility over deep thematic saturation, while maintaining rigor [40-43]. Interview notes were taken from electronic recordings and organized into templated matrices, codes, and subcodes that correspond to the study’s conceptual framework [42,43].

In Phase 1, notes from user development sessions were added to Excel matrices that included codes and subcodes guided by the intervention characteristics domain of the CFIR: relative advantage, adaptability, complexity, and design. This structured approach allowed the research team to efficiently synthesize user perspectives, identify patterns across participants, and implement timely revisions to the intervention content between development cycles. Three researchers independently conducted the qualitative analyses (LEH, SW, and DM).

An independent sample of participants (ie, did not participate in phase 1) was recruited from the Pediatric Pain Management Clinic at Stanford Medicine, Children’s Health. To be eligible for Phase 2, youth (1) were between ages 10 and 18 years old, (2) had a diagnosis of chronic (>3 mo) pain, and (3) reported at least moderate pain-related disability (Functional Disability Inventory >13) [44]. Eligibility criteria also required English literacy and access to a computer, smartphone, or tablet with an internet connection. Exclusion criteria included significant cognitive impairment or co-occurring medical or psychiatric conditions that could interfere with participation (eg, psychosis active suicidality).

Eligible participants were provided a link to a secure web-based screening form via REDCap, where they left contact information, completed the Functional Disability Inventory to screen for baseline pain-related disability, and the Patient Health Questionnaire-9, after which a RA followed up with a phone call to confirm eligibility. Eligible participants who selected a 1 or above (ie, several days to nearly every day) on the suicidal ideation question on the Patient Health Questionnaire-9 (“Thoughts that you would be better off dead, or of hurting yourself in some way”) underwent an additional safety assessment screening call with a qualified provider. Once eligibility was confirmed, enrollment procedures were identical to Phase 1. At baseline, youth completed self-report measures assessing demographic characteristics, pain history, pain intensity, pain-related disability, pain-related fear and avoidance, emotional functioning, and quality of life. Following this, the youth were given access to the password-protected platform where the intervention was hosted. All participants were assigned a deidentified username (eg, iGL_1) that they used to sign into the intervention platform. Participants were encouraged to engage with the intervention daily. Given the number of daily modules developed (see Results below), it was estimated that iGET Living would take ≈6 weeks to complete. After the first week of the intervention, youth completed a measure assessing treatment expectancy and credibility. After completing the treatment, the youth completed measures assessing treatment acceptability and satisfaction. Participants also participated in a semistructured exit interview. The self-report assessment battery completed at baseline was repeated at discharge and 3-month follow-up. Assessment of clinical outcomes across timepoints (ie, baseline, discharge, and 3-month follow-up) will be reported separately in a subsequent outcomes-focused manuscript.

A total of 15 youth were enrolled, with 5 in each iterative cycle, resulting in 3 total cohorts across the 3 iterative cycles. Youth were 15.6 years old on average (range 10‐18 years), with 73.3% assigned female at birth. All youth reported experiencing pain for 3+ years. The average pain rating for the sample was 5.8 (out of 10). Table 1 depicts participant demographic information across cycles. As outlined in Table 2, Phase 1 focused on iterative user-centered refinement through multiple cycles of end user feedback and real-time design iteration.

A summary of end user responses for the Intervention Content domain of the CFIR, along with the resulting action and iteration, is presented in Table 3. Detailed results for each iterative cycle (3 cycles in total) are described below.

Overall, youth described the digital delivery of iGET Living as flexible, allowing them to complete sessions at convenient times and frequencies. Youth liked the microsession format, noting it would be easier to “do a quick session here and there” as opposed to going into a doctor’s office, and appreciated that the intervention was mostly self-guided. Youth also reported that daily engagement with iGET Living was feasible. Barriers to daily engagement included physical symptoms (eg, pain, fatigue, dizziness), logistical challenges (eg, other doctors’ appointments, homework), and emotional readiness and motivation to engage.

Most participants noted that they would prefer to do iGET Living on a computer, not a smartphone, because the content would be easier to view on a larger screen, and it would be easier to type in module responses on a computer. However, youth expressed the desire for an app-based intervention that would be more accessible on a smartphone (“If it were designed differently, like an app, I would definitely use my phone.”), noting that being able to access the intervention on a smartphone increased flexibility with when and where they would engage in the intervention. Several youth noted no preference (eg, “probably both [computer and smartphone] depending on the day.”

Despite rating the modules’ favorability overall (Table 4), youth consistently described v1.0 of iGET Living as “textbook-like,” “too boring,” and “not something I would want to come back to.” Figure 2 shows content from several modules that included a voice-over video made in PowerPoint and examples of images of worksheets used. Youth reported several issues with the use of static images, with one youth sharing, “I want to be able to do something with the content, not just read it.”

Significant effort was made to simplify and reduce the text, which resulted in developing animated videos of core treatment concepts. Figure 3 shows the evolution of the Pain Dilemma animation from voice-over PowerPoint to VideoScribe to the final version, which was created in partnership with Kindea Labs. Overall, youth rated the videos very favorably (mean 3.6/4) and reported that the videos were “clear,” “easy to follow,” and “explained things pretty well.” Versions 1.0 and 2.0 of the prototype contained a module titled “Chronic Pain and the Pain Dilemma,” which introduced the distinction between acute and chronic pain and included an exercise based on the concept of creative hopelessness derived from acceptance and commitment therapy [53]. This element was designed to enhance youth readiness to engage with exposure-based activities by reflecting on the limits of avoidance and the potential benefits of values-driven action. In response to end user feedback, this module was divided into 2 shorter modules—What is Chronic Pain and The Pain Dilemma. The What is Chronic Pain module was also expanded to include additional psychoeducation on pain mechanisms (eg, how pain is processed in the brain, metaphors for understanding chronic pain), which had been missing from the initial prototype. The third and final cycle of user-centered interviews reflected that the content was clear and satisfactory (Table 4), as reflected in youth feedback: “The layout is easy to follow,” “Things are explained in an easy-to-understand way, and nothing is too wordy.”

For Phase 2, 107 youth were screened for eligibility between June 2023 and November 2024 (Figure 8). Of these, 38 youth enrolled in the study (42 were not interested in participating, 5 did not meet eligibility criteria upon further screening, and 5 were lost to follow-up). Of the 38 youth enrolled, 30 youth completed the study procedures (ie, engagement with intervention, completed nondaily and daily assessments). Youth reported an average age of 14.7 (SD 2.4), and 58.3% were assigned female at birth. Youth reported a range of pain diagnoses, including musculoskeletal pain, Ehlers-Danlos Syndrome, Complex Regional Pain Syndrome, and fibromyalgia, and over half (58.2%) of the sample reported experiencing pain for 3+ years. Youth reported an average pain intensity of 6.28 (SD 2.10), with 80.6% of youth reporting experiencing daily pain.

On the CEQ, participants reported moderate to high perceptions of iGET Living’s potential effectiveness after engaging with the intervention for one week. Summed scores for the credibility subscale were 19.71 (SD 4.34, range 9‐30) out of a possible 30. Summed scores for the Expectancy subscale were 17.96 (SD 5.83, range 3‐28) out of 30. Treatment satisfaction measured with the modified PSST was also high (mean 46.12, SD 11.46).

On the Theoretical Framework of Acceptability questionnaire, participants endorsed favorable ratings across most domains, including attitude toward the intervention (mean 3.32, SD 0.91), ethicality (mean 3.61, SD 0.91), perceived effectiveness (mean 3.35, SD 0.91), intervention coherence (mean 3.32, SD 0.98), and self-efficacy (mean 3.35, SD 0.84). Scores for burden (mean 3.19, SD 0.95) and opportunity costs (mean 2.90, SD 1.22) suggest some participants perceived challenges related to the effort required to engage in the intervention or competing demands. Overall, general acceptability was high (mean 3.81, SD 0.65).

 Exit interview data, which contained Likert-rated items and open-ended questions, further underscored the acceptability of the intervention (Table 5). Youth described the purpose of iGET Living as helping teens with chronic pain regain function, overcome avoidance, and reconnect with valued activities. They emphasized the importance of the intervention in “getting back to what you used to do,” “helping people with chronic pain get back to the things they enjoy,” and “providing a step-by-step guide to get out of the chronic pain bubble.” Ratings of intervention helpfulness were high, with mean scores of 3.6‐3.8 out of 4. Participants also highlighted areas for improvement, including increasing accessibility (eg, mobile-friendly or app-based formats) and adding more physical exercises. A modified exit interview was conducted with the 3 youth who withdrew from the study. Two of the youth stated that they already knew a lot of the intervention content:

The third youth also noted feeling as though it was not the right time for them to engage in this type of intervention:

An outline of the final intervention content can be found in Table 6.