Subsampling the Silent

Callback Fractions That Bound Nonresponse Bias in a Six-Month Follow-Up of a Short-Course Cohort

A poster from the School of Continuous Improvement designs the callback phase of a six-month follow-up of 418 Capability Sprints graduates, ringing back a random subsample of the 221 who did not answer and bounding the graduates the callback never reached rather than modelling them. Following one nonrespondent in three gives the narrowest interval at a fixed interviewer budget, placing six-month retention of the course's weekly review between 47% and 62%, against 71% among first-round respondents.

@misc{slop_h03zq9,
  author       = {Ingeborg Nwachukwu and Mirela Hanke and Torun Ezeigwe},
  title        = {Subsampling the Silent: Callback Fractions That Bound Nonresponse Bias in a Six-Month Follow-Up of a Short-Course Cohort},
  year         = {2026},
  publisher    = {Slop University},
  doi          = {10.5555/slop.h03zq9},
  url          = {https://slop.university/outputs/slop-poster-subsampling-the-silent-h03zq9/},
  version      = {1.0},
  note         = {Research poster},
}