title: Sampling permutations for Shapley value estimation

authors: Mitchell, Rory

subjects: interpretability

abstract: Game-theoretic attribution techniques based on Shapley values are used to interpret blackbox machine learning models, but their exact calculation is generally NP-hard, requiring approximation methods for non-trivial models. As the computation of Shapley values can be expressed as a summation over a set of permutations, a common approach is to sample a subset of these permutations for approximation. Unfortunately, standard Monte Carlo sampling methods can exhibit slow convergence, and more sophisticated quasi-Monte Carlo methods have not yet been applied to the space of permutations. To address this, we investigate new approaches based on two classes of approximation methods and compare them empirically. First, we demonstrate quadrature techniques in a RKHS containing functions of permutations, using the Mallows kernel in combination with kernel herding and sequential Bayesian quadrature. The RKHS perspective also leads to quasi-Monte Carlo type error bounds, with a tractable discrepancy measure defined on permutations. Second, we exploit connections between the hypersphere S d−2 and permutations to create practical algorithms for generating permutation samples with good properties. Experiments show the above techniques provide significant improvements for Shapley value estimates over existing methods, converging to a smaller RMSE in the same number of model evaluations

text: Sampling permutations for Shapley value estimation Game-theoretic attribution techniques based on Shapley values are used to interpret blackbox machine learning models, but their exact calculation is generally NP-hard, requiring approximation methods for non-trivial models. As the computation of Shapley values can be expressed as a summation over a set of permutations, a common approach is to sample a subset of these permutations for approximation. Unfortunately, standard Monte Carlo sampling methods can exhibit slow convergence, and more sophisticated quasi-Monte Carlo methods have not yet been applied to the space of permutations. To address this, we investigate new approaches based on two classes of approximation methods and compare them empirically. First, we demonstrate quadrature techniques in a RKHS containing functions of permutations, using the Mallows kernel in combination with kernel herding and sequential Bayesian quadrature. The RKHS perspective also leads to quasi-Monte Carlo type error bounds, with a tractable discrepancy measure defined on permutations. Second, we exploit connections between the hypersphere S d−2 and permutations to create practical algorithms for generating permutation samples with good properties. Experiments show the above techniques provide significant improvements for Shapley value estimates over existing methods, converging to a smaller RMSE in the same number of model evaluations

year: 2022

title: Designing for learner success (D4LS) at Otago Polytechnic: From an e-learning designer’s perspective

authors: Gedera, Dilani S.P.

subjects: curriculum

abstract: Otago Polytechnic (OP) is currently redesigning and redeveloping its programmes and courses under an institution-wide initiative called Designing for Learner Success (D4LS). This initiative has several phases—design, development, delivery, and evaluation. This article focuses on the processes and considerations in the development phase of D4LS, which adopted a collaborative and agile approach to developing high-quality course content, learning activities, assessments, and resources. A thematic analysis was conducted from a record of challenges and limitations encountered by e-learning designers in the development process. Four themes emerged as the key challenges: workload and timelines, products and process, communication, and capabilities and attitudes. Recommendations are offered for improving the support for e-learning designers and course developers who are undertaking similar institutional initiatives.

text: Designing for learner success (D4LS) at Otago Polytechnic: From an e-learning designer’s perspective Otago Polytechnic (OP) is currently redesigning and redeveloping its programmes and courses under an institution-wide initiative called Designing for Learner Success (D4LS). This initiative has several phases—design, development, delivery, and evaluation. This article focuses on the processes and considerations in the development phase of D4LS, which adopted a collaborative and agile approach to developing high-quality course content, learning activities, assessments, and resources. A thematic analysis was conducted from a record of challenges and limitations encountered by e-learning designers in the development process. Four themes emerged as the key challenges: workload and timelines, products and process, communication, and capabilities and attitudes. Recommendations are offered for improving the support for e-learning designers and course developers who are undertaking similar institutional initiatives.

year: 2016

title: "Takahi ngā takahanga o ngā tūpuna" - Tramp the pathways of our ancestors

authors: Williams, Taniwha

subjects: Māori health and wellbeing

abstract: The rise of reconnecting to holistic approaches to health to improve wellbeing outcomes for Māori has become increasingly prominent in recent years. Such developments have highlighted the need to introduce traditional Māori concepts, values and practices within whānau, hapū and iwi as vehicles for promoting and improving Māori health. This research had two objectives. Firstly, it aimed to explore the process of reclaiming mātauranga Māori (Māori knowledge systems) with my whānau who had limited access to te ao Māori (the Māori world). The second objective sought to explore the experiences of my whānau reconnecting with te reo me ōna tikanga (Māori language and culture). Using the Whiti Te Rā as a guide informed the design and structure of the wānanga (workshops). The Whiti Te Rā is a therapeutic model designed to improve health and wellbeing outcomes for Māori by developing and enhancing a cultural identity. Central to this model are six Māori customary practices and values that provide pathways to wellbeing and flourishing mauri. These dimensions also have synergies with other models of health – Te Whare Tapa Whā, Te Wheke. Four tāne (men) from my whānau took part in this research. We used the Pūrākau Method to record, explore, and analyse the narratives that emerged following each wānanga. The key findings from this research included connection to history, whakapapa and wairua; connection to pepeha and cultural practices; connection to self as a Māori; connection through whanaungatanga; and connection to taiao (the environment). This study showed that Māori models of health and wellbeing are consistent in demonstrating their effectiveness in connecting Māori to their language and culture. Despite the impact of colonisation, reconnection to customary practices and values was meaningful and valuable to my whānau. Future research is needed to revitalise, regenerate and reclaim a thriving Māori identity.

text: "Takahi ngā takahanga o ngā tūpuna" - Tramp the pathways of our ancestors The rise of reconnecting to holistic approaches to health to improve wellbeing outcomes for Māori has become increasingly prominent in recent years. Such developments have highlighted the need to introduce traditional Māori concepts, values and practices within whānau, hapū and iwi as vehicles for promoting and improving Māori health. This research had two objectives. Firstly, it aimed to explore the process of reclaiming mātauranga Māori (Māori knowledge systems) with my whānau who had limited access to te ao Māori (the Māori world). The second objective sought to explore the experiences of my whānau reconnecting with te reo me ōna tikanga (Māori language and culture). Using the Whiti Te Rā as a guide informed the design and structure of the wānanga (workshops). The Whiti Te Rā is a therapeutic model designed to improve health and wellbeing outcomes for Māori by developing and enhancing a cultural identity. Central to this model are six Māori customary practices and values that provide pathways to wellbeing and flourishing mauri. These dimensions also have synergies with other models of health – Te Whare Tapa Whā, Te Wheke. Four tāne (men) from my whānau took part in this research. We used the Pūrākau Method to record, explore, and analyse the narratives that emerged following each wānanga. The key findings from this research included connection to history, whakapapa and wairua; connection to pepeha and cultural practices; connection to self as a Māori; connection through whanaungatanga; and connection to taiao (the environment). This study showed that Māori models of health and wellbeing are consistent in demonstrating their effectiveness in connecting Māori to their language and culture. Despite the impact of colonisation, reconnection to customary practices and values was meaningful and valuable to my whānau. Future research is needed to revitalise, regenerate and reclaim a thriving Māori identity.

year: 2024