Transparency and Control in Platforms for Networked Markets

In this work, we analyze the worst case efficiency loss of online platform designs under a networked Cournot competition model. Inspired by some of the largest platforms today, the platform designs considered tradeoffs between transparency and control, namely, (i) open access, (ii) controlled allocation and (iii) discriminatory access. Our results show that open access designs incentivize increased production towards perfectly competitive levels and limit efficiency loss, while controlled allocation designs lead to producer-platform incentive misalignment, resulting in low participation and unbounded efficiency loss. We also show that discriminatory access designs seek a balance between transparency and control, and achieve the best of both worlds, maintaining high participation rates while limiting efficiency loss. We also study a model of consumer search cost which further distinguishes between the three designs

Transparency and Control in Platforms for Networked Markets

In this work, we analyze the worst case efficiency loss of online platform designs under a networked Cournot competition model. Inspired by some of the largest platforms today, the platform designs considered tradeoffs between transparency and control, namely, (i) open access, (ii) controlled allocation and (iii) discriminatory access. Our results show that open access designs incentivize increased production towards perfectly competitive levels and limit efficiency loss, while controlled allocation designs lead to producer-platform incentive misalignment, resulting in low participation and unbounded efficiency loss. We also show that discriminatory access designs seek a balance between transparency and control, and achieve the best of both worlds, maintaining high participation rates while limiting efficiency loss. We also study a model of consumer search cost which further distinguishes between the three designs

A comparison of different human papillomavirus tests in PreservCyt versus SurePath in a referral population-PREDICTORS 4

AbstractBackgroundTwo transport media, PreservCyt and SurePath, are widely used for cervical cytology screening. There are concerns that they may perform differently for HPV testing.ObjectivesA comparison of the performance of six different HPV tests in SurePath and PreservCyt in a referral population using two samples from each woman. The primary goal was to compare the performance of each test in the two media. Comparisons between assays and viral load comparisons between media were secondary aims.Study designTwo cervical samples were collected in random order at the same visit in women with abnormal cytology. One sample was placed in 20ml of PreservCyt and the other in 10ml of SurePath. Aliquots were taken for 4 DNA based tests: digene HC2 High-Risk HPV DNA Test, Abbott Realtime, BD Onclarity and Genera PapType, an RNA based test—: Hologic Aptima and a protein test: OncoHealth.Results630 sample pairs were included in the analyses. For all tests except the protein test sensitivities were in excess of 90% for CIN2+ and 95% for CIN3+ for both media and with no significant differences except for a lower sensitivity for CIN2+ of Aptima in SurePath (93% vs 98%, P=0.005). Specificity for <CIN2 was significantly better in Surepath for HC2, RealTime and Aptima, and generally lower relative signal strengths were seen with SurePath except for Onclarity, especially when it was the second sample.ConclusionsWe found similar sensitivity for CIN3+ in PreservCyt and SurePath for 5 nucleic acid tests in the two media in a referral population, but signal strength and positivity rates were lower in SurePath except for the Onclarity test. These results need to be replicated in a screening population

Individual detection of 14 high risk human papilloma virus genotypes by the PapType test for the prediction of high grade cervical lesions

AbstractBackgroundHR HPV genotypes when assayed collectively, achieve high sensitivity but low specificity for the prediction of CIN2+. Knowledge of the specific genotypes in an infection may facilitate the use of HR HPV detection in routine clinical practice.ObjectivesTo compare the rate of HR HPV detection and the accuracy of CIN2+ prediction between PapType test (Genera Biosystems) and other commercially available HR HPV assays, and to examine the value of full HPV genotyping.Study designPreservCyt samples from 1099 women referred for abnormal cervical cytology were used. CIN2+ was chosen as the primary end-point but CIN3+ was also evaluated. A hierarchy of HR HPV genotypes was created using PPV and this was used to create 3 groups of genotypes with potentially different management.ResultsThe PapType assay has a specificity of 22.4% and a sensitivity of 94.6% for CIN2+ prediction. Classification into Groups A (HPV33 and HPV16, very highly predictive), B (HPV31, 18, 52, 35, 58, 51 highly predictive) and C (HPV68, 45, 39, 66, 56, 59, intermediate predictive) could double the specificity (44.5%) but only slightly reduce the sensitivity for CIN2+ (91.5%) and CIN3+ (94.0%).ConclusionsThe PapType assay is a simple, reproducible and effective test for HR HPV detection and genotyping. HPV 33 was found to have a very high PPV and should therefore be managed as for HPV16