 Good day, I am Kaitlyn Frisbee, a doctoral student at the University of Pretoria in South Africa. I will be presenting a research article titled Smartphone Facilitated in-situ audiometry for community-based hearing testing. I would like to acknowledge my co-authors and the funders, namely the Newton Advanced Fellowship, the Global Disability Innovation Hub and the NIH. I also have to acknowledge that several of my co-authors are affiliated with the URX Group. The prevalence of hearing loss is increasing with an estimated 2.5 billion persons predicted to be affected globally by 2050. Scalable service delivery models using innovative technologies and task shifting are world health organization priorities to improve access to hearing care. Automated in-situ audiometry covered by noise attenuating ear cups facilitated by community health care workers could support more accessible hearing care. This study therefore aimed to determine the validity of automated smartphone facilitated in-situ audiometry for community-based hearing testing. Study objectives included determining the maximum permissible ambient noise levels, interdivisional liability, threshold accuracy and reliability in a clinical setting and performance in real-world settings. The maximum permissible ambient noise levels of Paltor 3M ear cups covering lexilumine hearing aids within-situ capabilities were determined by evaluating 15 adults with normal hearing according to the ISO standards. Participants were tested in a soundproof booth using free-field audiometry. The maximum permissible ambient noise levels were calculated by measuring the difference in attenuation between thresholds obtained with standard headphones, namely the TDH50Ps and the in-situ hearing aids covered by circumaural Paltor 3M ear cups to the prescribed maximum permissible ambient noise levels in the ISO standards. The maximum permissible ambient noise levels of the Paltor 3M ear cups covering the lexilumines are significantly higher than those of the TDH50Ps across all frequencies when testing down to 0 dB. The TDH50P headphones can be used during hearing assessments in a quiet room and thus as the maximum permissible ambient noise levels of the Paltor 3M ear cups covering the lexilumines are higher than those of the TDH50Ps, this confirms that the Paltor 3M ear cups are suitable for determining hearing thresholds in a quiet room. 14 lexilumine hearing aids were then tested to determine the inter-device reliability. The hearing aids were connected to a test box to CC coupler with a tone hook and prompted to play pure tones at various sound pressure levels in decibels across various frequencies. Inter-device performance reliability was high with all inter-device differences across all intensities and frequencies less than 3 dB, which is well within the plus minus 3 dB tolerance stipulated by the ISO standards. Frequency output was consistent and differed less than 0.7% between devices. 85 adult participants were then tested in a soundproof booth to determine the accuracy and test-retest reliability of automated in-situ audiometry performed independently compared to clinical pure-tone audiometry coupled to standard headphones facilitated by an audiologist. The first 39 participants were tested twice to determine test-retest reliability. Thresholds at the floor and ceiling sound levels of the hearing aid and clinical audiometer were removed from analysis to avoid biasing the results. 85.2% of hearing thresholds across all frequencies differed by 10 dB or less, which is consistent with other in-situ audiometry studies which also report a variance of approximately 10 dB. A statistically significant positive correlation coefficient across all frequencies is illustrated in this figure. The greatest correspondence was at 1000 Hz with 90.2% of thresholds within 10 dB of clinical audiometry. Thresholds at 4000 and 6000 Hz had the poorest correspondence with 82 and 80.1% of thresholds within 10 dB of clinical audiometry. This may be attributed to a few outliers at these frequencies. High test-retest reliability was demonstrated in this experiment with 93.2% of all test-retest hearing thresholds across frequencies differing by 10 dB or less. The lowest correspondence was measured at 500 Hz, where five extreme outliers were present. This illustrates the importance of quality control indices, particularly at 500 Hz. In a community setting, 144 adults were tested by three community health care workers to compare automated in-situ audiometry covered by circumaural Paltor 3M ear cups to automated mobile audiometry, namely the year test, coupled to standard headphones. The community health care workers conducted hearing assessments at the participants' homes. 44 participants were retested in the same session to determine test-retest reliability. Thresholds at the floor and ceiling sound levels of the hearing aid and the automated mobile audiometer removed from the analysis to avoid biasing the results. 83% of all automated in-situ thresholds across frequencies were within 10 dB of automated mobile audiometry. The greatest correspondence was at 2000 Hz, where 87.3% of thresholds were within 10 dB. Thresholds at 1000 Hz had the poorest correspondence, with 80.1% of thresholds within 10 dB. This may however also be due to a number of outliers or the tulip dome seal that could allow low frequency noise to enter and escape the ear canal. The poorer correspondences could also be attributed to the large differences in attenuation between the headphones used. The maximum permissible ambient noise levels for the Paltor 3M ear cups defined above are larger than those for the Sennheiser HD280 Pro headphones. The greatest correspondence at 2000 Hz is also where the maximum permissible ambient noise levels of the headphones are the most similar. High test-retest reliability was demonstrated in a sample of 44 participants, with mean differences ranging from 0 to 3.3 dB. Test-retest correspondence is illustrated in this figure. 91.3% of all test-retest hearing thresholds across frequencies differed by 10 dB or less. This study did not ever present with some limitations. The noise levels during the in-situ audiometry testing were not recorded in real time for all participants. This study did not involve children. This study highlights the potential of automated in-situ audiometry in clinical and real-world settings. Accurate and reliable hearing thresholds were obtained in both a clinical setting through a self-test and in a community-based setting facilitated by community healthcare workers. In-situ audiometry could thus make it possible to bring hearing testing and hearing aid fitting to the homes of individuals residing in low-resource settings. By bringing hearing healthcare services to those in need, in-situ audiometry has the potential to increase the reach and accessibility of hearing healthcare services. This article has been submitted to ear and hearing. Thank you for your time and attention.