This is a randomized controlled trial that will evaluate the effectiveness two different outreach strategies for a population-based breast cancer screening program at the VA Puget Sound among average risk female Veterans who are due for breast cancer screening.

This is a prospective, randomized controlled trial that will evaluate the effectiveness of two different outreach strategies in improving adherence to breast cancer screening via mammography.

Average risk female Veterans who are due for breast cancer screening (defined as aged 45-75 with no previous history of bilateral mastectomy, not under hospice care, and alive at the time of screening) will be identified through administrative data.

Veterans eligible for enrollment into the trial will be randomized in a 1:1 allocation using permuted block randomization (with random block sizes of 2 and 4) to the following interventions:

Arm 1: Automated phone opt-in message Intervention Type: Audiocare message requiring Veteran to confirm that they would like to participate in screening and have consult sent Arm 2: Opt-out scheduling Intervention Type: Consult automatically sent and Veteran called to schedule screening

Randomization will be stratified within arms by prior screening status (prior screener vs. never screener).

The study's primary outcome of interest is screening completion at 100 days post randomization. The study's secondary outcome of interest is screening scheduling at 100 days post randomization. Subgroup analysis aim 1 will explore whether the differences in breast cancer screening completion between investigational groups varies according to the Veterans' race/ethnicity. Subgroup analysis aim 2 will explore whether the differences in breast cancer screening scheduling between investigational groups varies according to the Veterans' race/ethnicity. Enrollment in the trial will occur between March 1, 2022 and August 31, 2022.

Inclusion Criteria:

• female Veterans aged 45-75
• assigned to a primary care provider at the VA Puget Sound as of January 1, 2022 with at least 1 year of prior data available
• due for breast cancer screening (have not had a mammogram in the last 12 months)

Exclusion Criteria:

• must not be any indication of current receipt of hospice care
• no record of recent death in the administrative data
• not scheduled for either a screening or diagnostic mammogram within the following 12 weeks from assessment.
• not have a personal history of bilateral mastectomy.

female only