Explanation for the choice of comparators

Two interventions are being tested in the current trial: standard SafeCare (i.e., the SafeCare model alone; active treatment control) and Smoke-Free Home SafeCare (treatment condition), the braided intervention that includes both SafeCare and the Smoke-Free Homes: Some Things are Better Outside (SFH) intervention. Standard SafeCare was chosen as the comparator because the purpose of the study is to evaluate the intervention effects of the added SHS prevention program integrated into SafeCare. Below, we describe the individual interventions and then describe Smoke-Free Home SafeCare, the integrated intervention that is being evaluated in this study.

Intervention description The SafeCare model

SafeCare is an 18-session home-based behavioral parenting program for parents of children ages 0 to 5 that addresses skills related to promoting positive parenting practices and reduced child maltreatment [32,33,34]. SafeCare is delivered in the home in both child-protective service settings and high-risk prevention settings by home visitors (i.e., SafeCare Providers) and is implemented in 29 US states and 8 countries. If a person is experiencing housing instability or housing challenges, sessions may take place in a location where the participant does not live, or virtually, at the discretion of the SafeCare provider. The specific setting in which SafeCare is delivered (at-risk prevention or CPS-involved) depends on the agency’s funding source.

SafeCare consists of 18 sessions, typically delivered weekly, divided into 3 modules (6 sessions per module). The three modules teach skills related to (1) parent–child/parent–infant interaction (PCI/PII), (2) home safety, and (3) child health. The parent–child interaction module targets behaviors to promote a safe, stable, nurturing relationship, and encourage social and emotional health in children through establishing daily routines and play activities. The home safety module offers parent education on common home hazards to promote a safe home environment for children. In this module, the provider and parent work together to identify and eliminate safety and health hazards and discuss the importance of parent supervision. The Child Health module offers parent education on common childhood illnesses and injuries; providers help parents implement a structured decision-making process to determine when and how to care for their child when sick or injured. In each module, SafeCare Providers use the explain-model-practice-feedback approach to teach the parent target SafeCare skills [35].

As part of NSTRC Implementation standards, fidelity monitoring occurs monthly for SafeCare Providers and is assessed by Certified SafeCare Coaches and Trainers (more about fidelity monitoring of SafeCare is described in aims 2 and 3).

Smoke-free homes: some things are better outside (SFH)

SFH is a brief evidence-based 6-week intervention that is effective in promoting home smoking bans and reducing secondhand smoke among people living in the USA [36,37,38]. SFH is made up of four parts: one mailing of print materials, followed by one 15–20-min coaching call, followed by two additional mailings of print materials that are sent to the participant. In the coaching call, the coach provides strategies to encourage and lead the participant through the five-step guide to creating a smoke-free home. The main outcomes of SFH are to create a smoke-free home and reduce secondhand smoke exposure, not smoking cessation; however, there are smoking cessation materials and support included in the print materials. SFH is grounded in Social Cognitive Theory and the Transtheoretical Model Stages of Change and uses persuasion, role modeling, goal setting, environmental cues, and written and verbal reinforcement of actions. Fidelity monitoring of the coaching call is a standard part of SFH implementation.

Smoke-Free Home SafeCare

Smoke-Free Home SafeCare (SFHSC) was developed by systematically braiding SafeCare and SFH, piloted, and refined during aim 1 of this study [29]. SFHSC consists of the standard three six-session SafeCare modules (i.e., parent–child/infant interaction, home safety, and child health) over 18 sessions, but includes the SFH intervention braided into the either Safety or Health module. The order of delivery for each module and the specific braided module used is determined by the provider. SFHSC is delivered by certified SafeCare providers or trained providers working toward certification who are employed by accredited agencies already delivering SafeCare in CPS or at-risk prevention settings, depending on the agency. Providers in the SFHSC condition receive additional training and coaching to deliver SFHSC before delivering the intervention and throughout the study. The initial and ongoing provider training process for providers in both study conditions is described in detail below.

Intervention training and support for providersStandard SafeCare

All SafeCare providers taking part in the trial will have completed the SafeCare Provider workshop, which is an NSTRC training and implementation requirement for all SafeCare providers. Before their first research family, providers in the Standard SafeCare group will be asked to complete a preparation call with the research team to discuss study procedures. Providers can earn US $20 for participating in this task. Apart from the preparation call, no additional training beyond standard SafeCare implementation coaching will be required. As part of standard SafeCare implementation fidelity monitoring requirements, all standard SafeCare providers will be asked to take part in one fidelity assessment per month with their assigned SafeCare Coach for their organization. Fidelity will be assessed via standard implementation procedures, which include uploading session recordings to the SafeCare portal, their coach listening to the session and rating fidelity on the SafeCare fidelity monitoring form, followed by a meeting where the coach and provider discuss their fidelity and the coach offers the provider positive and corrective feedback.

Smoke-Free SafeCare

Providers in the SFHSC group will receive an additional 3-h workshop delivered virtually by senior trainers at the NSTRC who will also act as SFHSC coaches for fidelity monitoring (see below for more details on the fidelity). SFHSC providers will be compensated US $150 for completing the SFHSC workshop. Before serving their first SFHSC family, the providers will have one preparation call with their SFHSC coach to discuss study procedures and ensure that the provider is prepared to deliver the content of the SFHSC sessions. Providers will then have a coaching meeting with their SFHSC coach to discuss fidelity monitoring for their first two sessions with their first two SFHSC families (four sessions total, 45–60 min per session). When a provider achieves fidelity with two SFHSC families (85% fidelity or above), they will be certified in SFHSC. SFHSC Providers will be compensated US $100 for completing the pre-session call and four coaching meetings to review the fidelity assessment (US $20 per task). To ensure continued fidelity for SFHSC, there will be one additional fidelity assessment conducted for the remaining research families that each SFHSC provider serves. SFHSC providers will be asked to record and upload every SFHSC session for every family to the SafeCare portal. The SFHSC coach will then select one session to review the remaining families for each provider.

Provider support for hybrid project research tasks

Providers in both conditions will be asked to participate in one refresher training on study methods per year throughout the study period. Separate research refresher training will be offered for SFHSC providers and providers in the Standard SafeCare condition. During the training, the research team will review study tasks, procedures, and intervention materials. The providers will also have the opportunity to ask questions and share the challenges and successes they are facing so the research team can help support and problem-solve collaboratively. Providers will be compensated US $60 for attending each 1-h refresher training.

Criteria for discontinuing or modifying allocated interventions

The research team piloted the integrated intervention during aim 1 of the study and made modifications. Both interventions are evidence-based, minimal risk, and broadly disseminated. Given this, the interventions will not be modified during the trial.

Strategies to improve adherence to interventions

The research team will maintain regular contact with both provider and parent participants throughout the research study. As part of NSTRC SafeCare training implementation standards, the providers are also trained in rapport building and cultural competency with the parents, which serves as a strategy to improve adherence to SafeCare.

Relevant concomitant care permitted or prohibited during the trial

Relevant concomitant care is not applicable to this study.

Provisions for post-trial care

No injuries are expected during this study. Participants are instructed in the informed consent form to contact the research team as soon as possible if they feel they have been harmed. There are no provisions for any ancillary and post-trail care, and no funds have been set aside to compensate participants if they have been harmed.

Outcomes Outcomes for aim 2

A description of measures, relevant intervention components, assessment time points, and associated intervention for aim 2 outcomes are presented in Table 1. Below are additional descriptions of the measures.

Table 1 Aim 2 primary and secondary outcomes for the hybrid type 1 trial evaluating Smoke-Free Home SafeCare Primary outcome

The primary outcome measure, the current presence of a full home smoking ban, is related to the SFH intervention target and has been validated in Smoke-Free Homes: Some Things Are Better Outside research [36,37,38]. Participants have a full smoking ban if smoking is not allowed anywhere in the home at any time at the time of completing the assessment. A partial ban is if smoking is allowed in some places or at some times, and no ban is if smoking is allowed anywhere inside the home. We will also assess what smoking products were covered by the ban (i.e., cigarettes, cigars, little cigars/cigarillos, and electronic nicotine delivery systems (ENDS)). Self-report data on home smoking bans have been shown to be highly valid and reliable [36,37,38]. We also will ask when the participant began restricting the smoking ban in their home (i.e., within the past month, within the past 6 months, within the past 6–12 months, 1–2 years, 3–5 years, or more than 5 years). The self-reported full smoking ban will be further validated using a passive air nicotine monitor placed in a room where the participant spends most of their time for 7 days. Passive air nicotine monitors have been used in previous Smoke-Free Homes: Some Things Are Better Outside research [38]. The passive air nicotine monitor is placed in the room in which the family spends the most amount of time for 7 days.

Secondary outcomes

Secondary outcomes related to SafeCare intervention targets include self-reported positive parenting behaviors over the past month [39], current parenting stress [40], perceived stress over the past month [41], current self-perceived knowledge and efficacy related to child health [42], and child supervision, safety, and injuries [43].

Secondary outcomes related to SFH intervention are not overtly targeted by the intervention but are measured because they are related to the main outcome and may be related to intervention spillover effects. Secondary SFH outcomes include current environmental factors that could affect SHS (i.e., type of home, if the participant rents or owns the home, if the landlord allows smoking), current vehicle situation and smoking rules in the vehicle, and current confidence in and importance of establishing smoke-free home rules. Current and prior lifetime tobacco use of the participant, tobacco products currently being used by someone else in the home, lifetime exposure to SHS, smoking in the same room or vehicle as the child in the past 7 days, and reasons for smoking indoors will be assessed [36,37,38]. Lastly, smoking cessation over the past 7 days will also be measured (i.e., past cessation attempts, types of tobacco products (i.e., cigarettes, cigars, little cigars/cigarillos, and ENDS)), and methods and resources used to help quit during the last cessation attempt.

Covariates

Standard demographics for parents include age (parent and child), sex, gender, race, ethnicity, education, employment status, income, relationship status, children (i.e., number of children living in the home, ages of target child), living situation, disability status, and the number of people who smoke who are living in the home.

Outcomes for aim 3

A description of implementation and process measures and assessment time points for aim 3 outcomes are presented in Table 2. Below are additional descriptions of the measures for aim 3.

Table 2 Aim 3 process and time and cost-benefit outcomes Time diaries

Provider time diaries were used in previous SafeCare research [44]. Providers will be asked to complete one time diary per SafeCare session for each family for the target intervention module via Qualtrics survey for each family a provider has who is completing Safety or Health in both study conditions. The data from the time diaries will be used for the cost analyses.

Session fidelity

Fidelity for this study will be assessed in two ways: coach-rated fidelity (NSTRC standard) and self-report fidelity for both Standard SafeCare and SFHSC. Both fidelity methods are described in detail below. As an NSTRC implementation standard, SafeCare providers are required to audio-record SafeCare sessions and submit audio recordings via the NSTRC portal. For coach-rated fidelity, certified SafeCare coaches listen to audio recordings of sessions, score each session for fidelity based on the SafeCare Provider Fidelity Checklist [45], and offer positive and corrective feedback to providers if needed. In one state, due to state regulations, the providers are unable to audio record SafeCare sessions for coach-rated fidelity. Therefore, it is standard for coach-rated fidelity with SafeCare providers in this state to be conducted in person, without audio recordings. The providers must achieve 85% fidelity to maintain SafeCare certification. Fidelity monitoring is also a standard part of the SFH intervention [36,37,38] and SFH fidelity will be integrated with SafeCare fidelity for the SFHSC providers.

Coach-rated fidelity

For providers in the Standard SafeCare group, session fidelity will be assessed per ongoing NSTRC implementation standards by the provider’s pre-assigned coach. Providers in the SFHSC group, however, will be asked to audio record all SafeCare sessions and submit the recordings to the SafeCare portal. After achieving SFHSC certification (described above), SFHSC fidelity will be monitored for the remaining families that a provider serves by the assigned SFHSC Coach. The SFHSC Coach will monitor fidelity by reviewing one audio recording per SafeCare provider for the remainder of the study. For SFHSC providers in the state that does not allow audio recordings, SFHSC Coaches will rely on self-rated fidelity and maintain contact with the provider. The SFHSC providers will be rated on the combined fidelity checklist that was created for the braided intervention in aim 1 of the current study, which includes items from the SafeCare Provider Fidelity Checklist [45] and the standard SFH fidelity items [36,37,38].

Self-rated fidelity

To accommodate state restrictions regarding recording sessions, the study team developed self-rated fidelity items to be completed by all providers in this study. Self-rated fidelity includes items from the SafeCare Provider Fidelity Checklist [45] and SFH fidelity items [36,37,38]. Self-rated fidelity items for SafeCare include whether the provider performed the fidelity item and their self-rating for that item. Self-rated fidelity will be completed for each session for each family that a provider serves and will be collected via Qualtrics

Parent engagement and satisfaction

Parent engagement items will be provider-reported and split across SafeCare sessions and will be collected weekly (up to six items per session), separately for each family via Qualtrics survey, while a provider has a family in the Safety or Health module (the research module). Parent satisfaction will be parent-reported and assessed using the SafeCare Parent Satisfaction Measure [43] at the 20-week assessment time point via REDCap.

Provider exit interview

SFHSC providers will be invited to participate in a brief exit interview to gather information about the SFHSC curriculum and delivery experiences.

Provider covariates

Standard demographics for providers include age, biological sex, gender, race, ethnicity, highest level of education completed and field of study, position at agency (full-time, part-time, contractor), income, years of experience working with families and delivering SafeCare, smoking status, and smoke-free home rules.

Participant timeline

Figure 1 presents the participant timeline for parents, including the time schedule of enrollment, interventions, and assessments.

Fig. 1

Parent participant timeline for the Smoke-Free Home SafeCare Trial

Note. aFor standard SafeCare, the target research module (safety or health) lasts six sessions/6 weeks. The entire Standard SafeCare intervention includes three six-session modules that last 18 weeks. bFor SFHSC, the target research module (SFHSC safety or SFHSC health) lasts six sessions/6 weeks. The entire SFHSC intervention includes three six-session modules that last 18 weeks. 1Indicates primary outcomes. 2Indicates secondary outcomes. *Both standard SafeCare and SFHSC consist of 3 6-week modules that take place over 18 sessions. SFHSC families receive the SFH materials braided into either the Safety or Health modules

Sample size

The sample size was determined based on previous SFH research [36,37,38] assuming 20% attrition, adjusting for clustering using design effects (DEFF = 1.5), and accounting also for the margin of equivalence in the non-inferiority analysis [46]. Assumptions were adequate power at 0.8 with alpha at 0.05 for the primary outcome, a current self-reported full smoking ban. Using the effect size from previous smoke-free home research, together with the power analysis for the non-inferiority analysis, we calculated that we needed 500 parent participants to allow us to detect an absolute difference of 16.4% in smoke-free homes between the two study arms. We used SAS 9.4 to conduct the power calculations (PROC POWER) and general math and the formula outlined in Merbook and Teerenstra (2015) to calculate the sample size.

Recruitment

To recruit providers, the research team received state-level SafeCare administrator approval to discuss the study with SafeCare Agency directors. Pending approval from agency directors, the research team scheduled a 30-min recruitment webinar to present the study to the agency director, team leads, and SafeCare providers. People who attended the recruitment webinar were compensated US $5 for their time. After the webinar, the providers had the opportunity to reach out to the research team to learn more about and consent to participate in the study. Provider consent happens on an individual basis. We have several agencies that have agreed to participate in the study; however, additional agencies may be added to the study if the research team deems it necessary for recruitment.

Once a provider is enrolled, they connect the research team to parents on their caseload who are willing to hear more about a SafeCare research opportunity. Providers share information about the research study (verbally and using fliers and/or branded magnets) with the parent either at intake or before the second session of the Home Safety or Child Health modules. If the parent is interested in learning more about participating in the research study, their provider will then help connect the parent to the research team in one of three ways: (1) the provider can call the research team directly when they are with the family, (2) parents can scan the QR code for the study on the recruitment flier and can call or text the research team, and (3) providers can share the family’s contact with the research team and the research team will contact the parent. On the initial call with an interested participant, the research team screens the parent for eligibility. All families who contact the research team receive a US $5 gift card for their time regardless of whether they are eligible, consent to participate, or choose to enroll in the study. Parents who are eligible and interested in participating in the study review the informed consent form with a member of the research team, and those who consent to participate are enrolled in the study. The provider will then continue Standard SafeCare or SFHSC with the enrolled parent. If a parent or provider chooses to not participate in the study, families will still receive SafeCare through the agency to which they have been referred as implementation at these agencies is ongoing.