Michał Jakubczyk
Current Organizations / Institutes
The organizations/institutes from the scholar's latest article
Previous Organizations / Institutes
The organizations / institutes from the scholar's other articles in the past ten years
Research Subjects
Michał Jakubczyk has a total of 178 co-authors. Here are the top co-authors by number of shared publications:
- Maciej Niewada
Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Warsaw, Poland
18 shared publications - Dominik Golicki
Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Warsaw, Poland
13 shared publications - Marcin Czech
Department of Pharmacoeconomics, Hospital Infection Control Team, Institute of Mother and Child, 01-211 Warsaw, Poland
5 shared publications Tomasz Hermanowski
5 shared publications- Beata Koń
National Health Fund, 02-528 Warsaw, Poland
4 shared publications - Bogumił Kamiński
Decision Analysis and Support Unit SGH Warsaw School of Economics Warsaw Poland
4 shared publications
Latest Publications
- Open Access
- 29 October 2026
- Published by Springer Nature in The European Journal of Health Economics
- p. 1-18
A consistency criterion for EQ-5D-5L bolt-on valuation
- 29 October 2026
- Published by Springer Nature in The European Journal of Health Economics
- p. 1-18
Open AccessA consistency criterion for EQ-5D-5L bolt-on valuation
- Open Access
- 28 May 2026
- Published by SAGE Publications in Medical Decision Making
- Vol. 46 (8) , 999-1011
Exploring Perceived Interactions between EQ-5D-5L and Bolt-ons Using Composite Time-Tradeoff Valuations: A Qualitative Study
Objectives: This study qualitatively explored how bolt-ons affect the perception of EQ-5D-5L core dimensions in a valuation context. Methods: Sixty Indonesian adults (aged 20–67 y, 50% female) each valued 10 health states using composite time tradeoff (cTTO). States were presented in either forward (EQ-5D-5L, then with 1 bolt-on, then 2) or backward (reversed sequence) order. Participants were assigned to 1 of 3 bolt-on dyads: vision and tiredness, cognition and social relationships, or skin irritation and self-confidence. In semistructured qualitative interviews, respondents described how adding or removing bolt-ons changed the perceived importance of the 5 core dimensions. We classified these changes as related either to measurement or to valuation, with the latter further categorized as a relative or absolute shift in importance. Results: Cognition and vision generated the most shifts in perceived importance in the forward and backward groups, respectively. Regardless of ordering group, most shifts occurred between the EQ-5D-5L alone and the version with 1 bolt-on (first presented in the dyad), with significantly fewer shifts observed between the 1-bolt-on and 2-bolt-on states. In the forward group, most shifts were classified as measurement (56%) or relative preference (29%), while the reverse was true in the backward group: relative preference (53%) or measurement (31%). Absolute preference was least common across both groups. Conclusions: This is the first study to explore how individuals reason when valuing EQ-5D-5L+bolt-on health states. Our findings suggest that interactions between dimensions are complex and may be influenced by presentation order. Further qualitative research should directly investigate absolute preferential reasoning. Highlights: No studies have qualitatively explored how individuals value EQ-5D health states with bolt-ons. Understanding how bolt-ons influence reasoning and interact with core dimensions is crucial for informing valuation methods and modeling strategies. Our findings show that bolt-ons can alter how participants perceive the importance of EQ-5D-5L dimensions, although changes are mostly not preference driven. Participants often rely on accessible reasoning, such as conceptual associations between dimensions. Effects vary by the bolt-on used and presentation order. Interactions between bolt-ons and core dimensions complicate efforts to develop robust valuation approaches. Future qualitative studies should aim to capture preference-based reasoning, while quantitative work is needed to disentangle preferential from nonpreferential effects.
- 28 May 2026
- Published by SAGE Publications in Medical Decision Making
- Vol. 46 (8) , 999-1011
Open AccessExploring Perceived Interactions between EQ-5D-5L and Bolt-ons Using Composite Time-Tradeoff Valuations: A Qualitative Study
Objectives: This study qualitatively explored how bolt-ons affect the perception of EQ-5D-5L core dimensions in a valuation context. Methods: Sixty Indonesian adults (aged 20–67 y, 50% female) each valued 10 health states using composite time tradeoff (cTTO). States were presented in either forward (EQ-5D-5L, then with 1 bolt-on, then 2) or backward (reversed sequence) order. Participants were assigned to 1 of 3 bolt-on dyads: vision and tiredness, cognition and social relationships, or skin irritation and self-confidence. In semistructured qualitative interviews, respondents described how adding or removing bolt-ons changed the perceived importance of the 5 core dimensions. We classified these changes as related either to measurement or to valuation, with the latter further categorized as a relative or absolute shift in importance. Results: Cognition and vision generated the most shifts in perceived importance in the forward and backward groups, respectively. Regardless of ordering group, most shifts occurred between the EQ-5D-5L alone and the version with 1 bolt-on (first presented in the dyad), with significantly fewer shifts observed between the 1-bolt-on and 2-bolt-on states. In the forward group, most shifts were classified as measurement (56%) or relative preference (29%), while the reverse was true in the backward group: relative preference (53%) or measurement (31%). Absolute preference was least common across both groups. Conclusions: This is the first study to explore how individuals reason when valuing EQ-5D-5L+bolt-on health states. Our findings suggest that interactions between dimensions are complex and may be influenced by presentation order. Further qualitative research should directly investigate absolute preferential reasoning. Highlights: No studies have qualitatively explored how individuals value EQ-5D health states with bolt-ons. Understanding how bolt-ons influence reasoning and interact with core dimensions is crucial for informing valuation methods and modeling strategies. Our findings show that bolt-ons can alter how participants perceive the importance of EQ-5D-5L dimensions, although changes are mostly not preference driven. Participants often rely on accessible reasoning, such as conceptual associations between dimensions. Effects vary by the bolt-on used and presentation order. Interactions between bolt-ons and core dimensions complicate efforts to develop robust valuation approaches. Future qualitative studies should aim to capture preference-based reasoning, while quantitative work is needed to disentangle preferential from nonpreferential effects.
- Open Access
- 12 November 2025
- Published by Springer Nature in The European Journal of Health Economics
- Vol. 27 (4) , 893-903
Eliciting discounting model and direction at the individual level with time trade-off follow-up questions
Objective Time preference is increasingly considered in health state valuation. As its inclusion impacts the produced value sets, it is important to account for it using the correct specification. Various discounting functions have been used, and both directions of time preference have been identified. I aimed to extend the composite time-trade off task (composite TTO, cTTO) by follow-up questions (TTOFUs) to identify the discounting function and direction for individual respondents. Methods Respondents completed cTTO tasks for 6 EQ-5D-5L health states. If utility exceeded 0.1, three TTOFUs (Q1–Q3) were posed. Each TTOFU modified the indifference-yielding alternative by halving durations (Q1) or adding a 5-year lead-time in full health (Q2) or a 5-year lag-time in the valued state (Q3). As shown in the paper, the pattern of Q1–Q3 answers unambiguously discerns the discounting function (exponential, power, or hyperbolic) and direction. Results Data from 148 respondents, 16 health states, and 577 respondent-state pairs were analysed. Only 20.4% of pairs yielded theoretically-plausible patterns, and among those 60% imply no time preference. For Q2 and Q3, responses mostly implied negative (\(57\%\)) and positive (\(63\%\)) time preference, respectively. Majority-rule pooling within respondents produced a pattern not matching the considered discounting models but that can arise when quality-of-life and longevity are combined additively, not multiplicatively as in the quality-adjusted life years (QALY) model. Conclusions Standard discounting models poorly fit observed choices in TTO-like questions. The discounting parameters measured in other studies may be driven by other phenomena, including departures from the QALY model. Hence, careful interpretation of estimated parameters is warranted, and future studies are recommended.- 12 November 2025
- Published by Springer Nature in The European Journal of Health Economics
- Vol. 27 (4) , 893-903
Open AccessEliciting discounting model and direction at the individual level with time trade-off follow-up questions
Objective Time preference is increasingly considered in health state valuation. As its inclusion impacts the produced value sets, it is important to account for it using the correct specification. Various discounting functions have been used, and both directions of time preference have been identified. I aimed to extend the composite time-trade off task (composite TTO, cTTO) by follow-up questions (TTOFUs) to identify the discounting function and direction for individual respondents. Methods Respondents completed cTTO tasks for 6 EQ-5D-5L health states. If utility exceeded 0.1, three TTOFUs (Q1–Q3) were posed. Each TTOFU modified the indifference-yielding alternative by halving durations (Q1) or adding a 5-year lead-time in full health (Q2) or a 5-year lag-time in the valued state (Q3). As shown in the paper, the pattern of Q1–Q3 answers unambiguously discerns the discounting function (exponential, power, or hyperbolic) and direction. Results Data from 148 respondents, 16 health states, and 577 respondent-state pairs were analysed. Only 20.4% of pairs yielded theoretically-plausible patterns, and among those 60% imply no time preference. For Q2 and Q3, responses mostly implied negative (\(57\%\)) and positive (\(63\%\)) time preference, respectively. Majority-rule pooling within respondents produced a pattern not matching the considered discounting models but that can arise when quality-of-life and longevity are combined additively, not multiplicatively as in the quality-adjusted life years (QALY) model. Conclusions Standard discounting models poorly fit observed choices in TTO-like questions. The discounting parameters measured in other studies may be driven by other phenomena, including departures from the QALY model. Hence, careful interpretation of estimated parameters is warranted, and future studies are recommended. - Open Access
- 18 August 2025
- Published by Wolters Kluwer Health in Medical Care
- Vol. 63 (10) , 771-778
Revisiting the Valuation of Child Health-Related Quality of Life
Objectives: In 2013, the EQ-5D-Y-3L valuation study conducted by Craig and colleagues (ie, the original study) of child health-related quality of life (HRQoL) revealed that U.S. respondents often found it burdensome and guilt-inducing to choose between hypothetical health problems of children. This study introduces an alternative approach where respondents sequentially relieve the health problems of a 10-year-old child for 1 week. Methods: We conducted a discrete choice experiment (DCE) survey (N=631) with paired comparisons and kaizen tasks. Each kaizen task displayed a single profile of a child’s HRQoL using the EQ-5D-Y-3L descriptive system and asked respondents to select first, second, and third improvements for the child’s problems. Combining the preference evidence, a conditional logit model was estimated to produce EQ-5D-Y-3L values on an “experience” scale, where positive values signify experiences better than “being in a coma” and negative values worse. Results: All 10 main effects were statistically significant (P<0.01), with the highest value placed on alleviating pain and discomfort. The worst-case scenario (33333) had a value of −0.337 on the experience scale, indicating it is worse than a coma. These new estimates highly correlate with the original U.S. EQ-5D-Y-3L values (Pearson correlation=0.726; Spearman correlation=0.794). Conclusion: This innovative approach to child health valuation replaces paired comparisons with Kaizen tasks, reducing respondent burden and study costs. Its use of experience scaling, instead of QALYs, aligns with U.S. guidelines (eg, the Inflation Reduction Act of 2022) and summarizes child HRQoL gains for health technology assessment.
- 18 August 2025
- Published by Wolters Kluwer Health in Medical Care
- Vol. 63 (10) , 771-778
Open AccessRevisiting the Valuation of Child Health-Related Quality of Life
Objectives: In 2013, the EQ-5D-Y-3L valuation study conducted by Craig and colleagues (ie, the original study) of child health-related quality of life (HRQoL) revealed that U.S. respondents often found it burdensome and guilt-inducing to choose between hypothetical health problems of children. This study introduces an alternative approach where respondents sequentially relieve the health problems of a 10-year-old child for 1 week. Methods: We conducted a discrete choice experiment (DCE) survey (N=631) with paired comparisons and kaizen tasks. Each kaizen task displayed a single profile of a child’s HRQoL using the EQ-5D-Y-3L descriptive system and asked respondents to select first, second, and third improvements for the child’s problems. Combining the preference evidence, a conditional logit model was estimated to produce EQ-5D-Y-3L values on an “experience” scale, where positive values signify experiences better than “being in a coma” and negative values worse. Results: All 10 main effects were statistically significant (P<0.01), with the highest value placed on alleviating pain and discomfort. The worst-case scenario (33333) had a value of −0.337 on the experience scale, indicating it is worse than a coma. These new estimates highly correlate with the original U.S. EQ-5D-Y-3L values (Pearson correlation=0.726; Spearman correlation=0.794). Conclusion: This innovative approach to child health valuation replaces paired comparisons with Kaizen tasks, reducing respondent burden and study costs. Its use of experience scaling, instead of QALYs, aligns with U.S. guidelines (eg, the Inflation Reduction Act of 2022) and summarizes child HRQoL gains for health technology assessment.
- Open Access
- 26 February 2025
- Published by Springer Nature in PharmacoEconomics
- Vol. 43 (6) , 665-675
Making Composite Time Trade-Off Sensitive for Worse-than-Dead Health States
Objective The utilities elicited with the composite time trade-off (cTTO) method for health states worse-than-dead (WTD) often correlate poorly with other severity measures, indicating a poor sensitivity of cTTO. We aimed to explore modifications to cTTO to better understand this phenomenon and identify potential improvements. Methods A total of 480 respondents completed an online TTO interview, each valuing 12 EQ-5D-5L health states. The participants were randomized into four arms, A–D. Arm A followed the standard cTTO, serving as a reference. In arm B, we removed the sorting question comparing immediate death versus 10 years in a valued state. Arm C allowed for utility values \(<-1\) by reducing the time in the valued state in the lead-time TTO (LT-TTO) part of cTTO. In arm D, we randomly selected the starting negative utility in LT-TTO. Utility value distributions, correlations between utilities and level sum score (LSS), and inconsistencies between Pareto-ordered states were analyzed. Results Arm A replicated the lack of significant correlation between LSS and the negative utility observed in previous work. Of the experimental arms, only arm B exhibited a significant negative correlation. Compared with arm A, arm B produced a higher proportion of WTD states (\(46.5\%\) versus \(26.3\%\)), less negative utility for WTD states on average (\(-0.571\) versus \(-0.752\)), and a lower mean censored utility for 55555 (\(-0.486\) versus \(-0.406\)). Conclusions The observed lack of correlation between LSS and utility for WTD states appears linked to the use of comparison with immediate death in the sorting question. LT-TTO is capable of eliciting utility values in a way that is sensitive to severity. Modifying the initial questions in cTTO to identify whether health states are BTD or WTD should be considered.- 26 February 2025
- Published by Springer Nature in PharmacoEconomics
- Vol. 43 (6) , 665-675
Open AccessMaking Composite Time Trade-Off Sensitive for Worse-than-Dead Health States
Objective The utilities elicited with the composite time trade-off (cTTO) method for health states worse-than-dead (WTD) often correlate poorly with other severity measures, indicating a poor sensitivity of cTTO. We aimed to explore modifications to cTTO to better understand this phenomenon and identify potential improvements. Methods A total of 480 respondents completed an online TTO interview, each valuing 12 EQ-5D-5L health states. The participants were randomized into four arms, A–D. Arm A followed the standard cTTO, serving as a reference. In arm B, we removed the sorting question comparing immediate death versus 10 years in a valued state. Arm C allowed for utility values \(<-1\) by reducing the time in the valued state in the lead-time TTO (LT-TTO) part of cTTO. In arm D, we randomly selected the starting negative utility in LT-TTO. Utility value distributions, correlations between utilities and level sum score (LSS), and inconsistencies between Pareto-ordered states were analyzed. Results Arm A replicated the lack of significant correlation between LSS and the negative utility observed in previous work. Of the experimental arms, only arm B exhibited a significant negative correlation. Compared with arm A, arm B produced a higher proportion of WTD states (\(46.5\%\) versus \(26.3\%\)), less negative utility for WTD states on average (\(-0.571\) versus \(-0.752\)), and a lower mean censored utility for 55555 (\(-0.486\) versus \(-0.406\)). Conclusions The observed lack of correlation between LSS and utility for WTD states appears linked to the use of comparison with immediate death in the sorting question. LT-TTO is capable of eliciting utility values in a way that is sensitive to severity. Modifying the initial questions in cTTO to identify whether health states are BTD or WTD should be considered. - 6 January 2025
- Published by Elsevier in Case Studies on Transport Policy
- Vol. 19
Why not share it? — Understanding preferences for car sharing services in Warsaw, Poland
- 6 January 2025
- Published by Elsevier in Case Studies on Transport Policy
- Vol. 19
Why not share it? — Understanding preferences for car sharing services in Warsaw, Poland
- Open Access
- 2 January 2025
- Published by SAGE Publications in Clinical Trials
- Vol. 22 (3) , 342-351
Central statistical monitoring in clinical trial management: A scoping review
Background: Clinical trials handle a huge amount of data which can be used during the trial to improve the ongoing study conduct. It is suggested by regulators to implement the remote approach to evaluate clinical trials by analysing collected data. Central statistical monitoring helps to achieve that by employing quantitative methods, the results of which are a basis for decision-making on quality issues. Methods: This article presents a scoping review which is based on a systematic and iterative approach to identify and synthesise literature on central statistical monitoring methodology. In particular, we investigated the decision-making processes (with emphasis on quality issues) of central statistical monitoring methodology and its place in the clinical trial workflow. We reviewed papers published over the last 10 years in two databases (Scopus and Web of Science) with a focus on data mining algorithms of central statistical monitoring and its benefit to the quality of trials. Results: As a result, 24 scientific papers were selected for this review, and they consider central statistical monitoring at two levels. First, the perspective of the central statistical monitoring process and its location in the study conduct in terms of quality issues. Second, central statistical monitoring methods categorised into practices applied in the industry, and innovative methods in development. The established methods are discussed through the prism of categories of their usage. In turn, the innovations refer to either research on new methods or extensions to existing ones. Discussion: Our review suggests directions for further research into central statistical monitoring methodology – including increased application of multivariate analysis and using advanced distance metrics – and guidance on how central statistical monitoring operates in response to regulators’ requirements.
- 2 January 2025
- Published by SAGE Publications in Clinical Trials
- Vol. 22 (3) , 342-351
Open AccessCentral statistical monitoring in clinical trial management: A scoping review
Background: Clinical trials handle a huge amount of data which can be used during the trial to improve the ongoing study conduct. It is suggested by regulators to implement the remote approach to evaluate clinical trials by analysing collected data. Central statistical monitoring helps to achieve that by employing quantitative methods, the results of which are a basis for decision-making on quality issues. Methods: This article presents a scoping review which is based on a systematic and iterative approach to identify and synthesise literature on central statistical monitoring methodology. In particular, we investigated the decision-making processes (with emphasis on quality issues) of central statistical monitoring methodology and its place in the clinical trial workflow. We reviewed papers published over the last 10 years in two databases (Scopus and Web of Science) with a focus on data mining algorithms of central statistical monitoring and its benefit to the quality of trials. Results: As a result, 24 scientific papers were selected for this review, and they consider central statistical monitoring at two levels. First, the perspective of the central statistical monitoring process and its location in the study conduct in terms of quality issues. Second, central statistical monitoring methods categorised into practices applied in the industry, and innovative methods in development. The established methods are discussed through the prism of categories of their usage. In turn, the innovations refer to either research on new methods or extensions to existing ones. Discussion: Our review suggests directions for further research into central statistical monitoring methodology – including increased application of multivariate analysis and using advanced distance metrics – and guidance on how central statistical monitoring operates in response to regulators’ requirements.
- Open Access
- 29 November 2024
- Published by Springer Nature in Scientific Data
- Vol. 11 (1) , 1-23
Air quality and transport behaviour: sensors, field, and survey data from Warsaw, Poland
The present study describes the data sets produced in Warsaw, Poland with the aim of developing tools and methods for the implementation of human-centred and data-driven solutions to the enhancement of sustainable mobility transition. This study focuses on school commutes and alternatives to private cars for children drop off and pick up from primary schools. The dataset enables the complex analysis of interactions between determinants of transport mode choice, revealed choices, and air quality impact. We draw on four data collection methods, namely, (i) air quality and noise sensors’ measurements, (ii) in-person observations of transport behaviours, (iii) travel diaries, and (iv) social surveys. Moreover, all trip data from travel diaries are complemented with the calculated attributes of alternative travel modes. The data produced in the project can be also combined with publicly available information on air quality, public transport schedules, and traffic flows. The present data sets help to open new venues for interdisciplinary analyses of sustainable mobility transition effectiveness and efficiency.
- 29 November 2024
- Published by Springer Nature in Scientific Data
- Vol. 11 (1) , 1-23
Open AccessAir quality and transport behaviour: sensors, field, and survey data from Warsaw, Poland
The present study describes the data sets produced in Warsaw, Poland with the aim of developing tools and methods for the implementation of human-centred and data-driven solutions to the enhancement of sustainable mobility transition. This study focuses on school commutes and alternatives to private cars for children drop off and pick up from primary schools. The dataset enables the complex analysis of interactions between determinants of transport mode choice, revealed choices, and air quality impact. We draw on four data collection methods, namely, (i) air quality and noise sensors’ measurements, (ii) in-person observations of transport behaviours, (iii) travel diaries, and (iv) social surveys. Moreover, all trip data from travel diaries are complemented with the calculated attributes of alternative travel modes. The data produced in the project can be also combined with publicly available information on air quality, public transport schedules, and traffic flows. The present data sets help to open new venues for interdisciplinary analyses of sustainable mobility transition effectiveness and efficiency.
- Open Access
- 1 November 2023
- Published by Elsevier in Value in Health
- Vol. 27 (1) , 95-103
This Dead or That Dead: Framing Effects in the Evaluation of Health States
- 1 November 2023
- Published by Elsevier in Value in Health
- Vol. 27 (1) , 95-103
Open AccessThis Dead or That Dead: Framing Effects in the Evaluation of Health States