Statistical Challenges in Online Controlled Experiments: A Review of A/B Testing Methodology

The rise of internet-based services and products in the late 1990's brought about an unprecedented opportunity for online businesses to engage in large scale data-driven decision making. Over the past two decades, organizations such as Airbnb, Alibaba, Amazon, Baidu, Booking, Alphabet's Google, LinkedIn, Lyft, Meta's Facebook, Microsoft, Netflix, Twitter, Uber, and Yandex have invested tremendous resources in online controlled experiments (OCEs) to assess the impact of innovation on their customers and businesses. Running OCEs at scale has presented a host of challenges requiring solutions from many domains. In this paper we review challenges that require new statistical methodologies to address them. In particular, we discuss the practice and culture of online experimentation, as well as its statistics literature, placing the current methodologies within their relevant statistical lineages and providing illustrative examples of OCE applications. Our goal is to raise academic statisticians' awareness of these new research opportunities to increase collaboration between academia and the online industry

Overview of Security Plan for Offshore Floating Nuclear Plant

A new Offshore Floating Nuclear Plant (OFNP) concept with high potential for attractive economics and an unprecedented level of safety is presented, along with an overview of work done in the area of security. The OFNP creatively combines state-of-the-art Light Water Reactors (LWRs) with floating platforms such as those used in offshore oil/gas operations, both of which are well-established technologies which can allow implementation on a time scale consistent with combating climate change in the near future. OFNP is a plant that can be entirely built within a floating platform in a shipyard, transferred to the site. OFNP eliminates earthquakes and tsunamis as accident precursors; its ocean-based passive safety systems eliminate the loss of ultimate heat sink accident by design. The defense of an OFNP poses new security opportunities and challenges compared to land-based plants. Such a plant can be more easily defended by virtue of the clear 360 degree lines of sight and the relative ease of identifying surface threats. Conversely the offshore plant is potentially vulnerable to underwater approaches by mini-submarines and divers. We investigate security considerations of the OFNP applicable to two potential plant options, an OFNP-300 with a 300 MWe reactor, and an OFNP-1100 with an 1100 MWe reactor. Three innovative security system approaches could be combined for the offshore plant. The first is a comprehensive detection system which integrates radar, sonar and unmanned vehicles for a long distance overview of the vicinity of the plant. The second approach is the use of passive physical barriers about 100 meters from the plant, which will force a fast-moving power boat to lose speed or stop at the barrier allowing the plant security force more time to respond. The third approach takes advantage of the offshore plant siting and the monthly or biweekly rotation of crew to reduce the total on-plant and onshore security force by using the off-duty security force on the plant as a reserve force. Through the use of these approaches, the OFNP-300 should be able to achieve a similar security cost (on a per Megawatt basis) as land-based plants of similar or somewhat larger power rating. Due to non-linear scaling of cost, the security cost of the OFNP-1100 has the potential to be reduced significantly compared to its land-based equivalents

Implementing lifestyle-related treatment modalities in osteoarthritis care:Identification of implementation strategies using the Consolidated Framework for Implementation Research-Expert Recommendations for Implementing Change matching tool

Aims: Despite recommendations in international clinical guidelines, lifestyle-related treatment modalities (LRTMs) are currently underutilised in the conservative treatment of patients with hip and/or knee osteoarthritis. This study aimed to identify implementation strategies in order to address barriers to implementing LRTMs from the perspective of healthcare professionals (HCPs). Methods: The Consolidated Framework for Implementation Research (CFIR)-Expert Recommendations for Implementing Change (ERIC) Implementation Strategy Matching Tool was applied. First, previously identified influencing factors among primary and secondary HCPs were mapped onto the corresponding CFIR constructs/subconstructs by two researchers. Second, the CFIR-based barriers relevant for all HCPs were entered into the tool. Third, the CFIR-based barriers specific to one or more subgroups of HCPs served as additional input for the tool. Finally, a selection of ERIC implementation strategies was made based on the tool's output. Results: Fourteen implementation strategies were selected. The strategy most endorsed by the tool was ‘build a coalition’. Eight of the selected strategies belonged to the ERIC cluster ‘develop stakeholder interrelationships’. Other strategies were part of the clusters ‘use evaluative and iterative strategies’ (n = 3), ‘utilise financial strategies’ (n = 2), and ‘engage consumers’ (n = 1). Conclusions: The findings emphasise the importance of an interdisciplinary approach when addressing the implementation of LRTMs in osteoarthritis care. The final selection of implementation strategies forms the basis for a tailored implementation plan. Future work should focus on further operationalising the implementation strategies and evaluating the effectiveness of the resulting implementation plan.</p