The impact of integrated care on health care utilization and costs in a socially deprived urban area in Germany: A difference-in-differences approach within an event-study framework.

We investigated the impact of an integrated care initiative in a socially deprived urban area in Germany. Using administrative data, we empirically assessed the causal effect of its two sub-interventions, which differed by the extent to which their instruments targeted the supply and demand side of healthcare provision. We addressed confounding using propensity score matching via the Super Learner machine learning algorithm. For our baseline model, we used a two-way fixed-effects difference-in-differences approach to identify causal effects. We then employed difference-in-differences analyses within an event-study framework to explore the heterogeneity of treatment effects over time, allowing us to disentangle the effects of the sub-interventions and improve causal interpretation and generalizability. The initiative led to a significant increase in hospital and emergency admissions and non-hospital outpatient visits, as well as inpatient, non-hospital outpatient, and total costs. Increased utilization may indicate that the intervention improved access to care or identified unmet need.

Comparing methods for estimating causal treatment effects of administrative health data: A plasmode simulation study.

Estimating the causal effects of health policy interventions is crucial for policymaking but is challenging when using real-world administrative health care data due to a lack of methodological guidance. To help fill this gap, we conducted a plasmode simulation using such data from a recent policy initiative launched in a deprived urban area in Germany. Our aim was to evaluate and compare the following methods for estimating causal effects: propensity score matching, inverse probability of treatment weighting, and entropy balancing, all combined with difference-in-differences analysis, augmented inverse probability weighting, and targeted maximum likelihood estimation. Additionally, we estimated nuisance parameters using regression models and an ensemble learner called superlearner. We focused on treatment effects related to the number of physician visits, total health care cost, and hospitalization. While each approach has its strengths and weaknesses, our results demonstrate that the superlearner generally worked well for handling nuisance terms in large covariate sets when combined with doubly robust estimation methods to estimate the causal contrast of interest. In contrast, regression-based nuisance parameter estimation worked best in small covariate sets when combined with singly robust methods.

Navigating the Future of Organisational Health Services Research in Germany and beyond: a Position Paper. / Die Zukunft der organisationsbezogenen Versorgungsforschung in Deutschland und darüber hinaus ­ ein Positionspapier.

BACKGROUND: Recent analyses have shown that in health services research in Germany, healthcare organisations are often considered primarily as a study setting, without fully taking their complex organisational nature into account, neither theoretically nor methodologically. Therefore, an initiative was launched to analyse the state of Organisational Health Services Research (OHSR) in Germany and to develop a strategic framework and road map to guide future efforts in the field. This paper summarizes positions that have been jointly developed by consulting experts from the interdisciplinary and international scientific community. METHODS: In July 2023, a scoping workshop over the course of three days was held with 32 (inter)national experts from different research fields centred around OHSR topics using interactive workshop methods. Participants discussed their perspectives on OHSR, analysed current challenges in OHSR in Germany and developed key positions for the field's development. RESULTS: The seven agreed-upon key positions addressed conceptual and strategic aspects. There was consensus that the field required the development of a research agenda that can guide future efforts. On a conceptual level, the need to address challenges in terms of interdisciplinarity, terminology, organisation(s) as research subjects, international comparative research and utilisation of organisational theory was recognized. On a strategic level, requirements with regard to teaching, promotion of interdisciplinary and international collaboration, suitable funding opportunities and participatory research were identified. CONCLUSIONS: This position paper seeks to serve as a framework to support further development of OHSR in Germany and as a guide for researchers and funding organisations on how to move OHSR forward. Some of the challenges discussed for German OHSR are equally present in other countries. Thus, this position paper can be used to initiate fruitful discussions in other countries.

How social networks influence the local implementation of initiatives developed in quality improvement collaboratives in health care: A qualitative process study.

BACKGROUND: Quality improvement collaboratives (QICs) have facilitated cross-organizational knowledge exchange in health care. However, the local implementation of many quality improvement (QI) initiatives continues to fail, signaling a need to better understand the contributing factors. Organizational context, particularly the role of social networks in facilitating or hindering implementation within organizations, remains a potentially critical yet underexplored area to addressing this gap. PURPOSE: We took a dynamic process perspective to understand how QI project managers' social networks influence the local implementation of QI initiatives developed through QICs. METHODOLOGY: We explored the case of a QIC by triangulating data from an online survey, semistructured interviews, and archival documents from 10 organizations. We divided implementation into four stages and employed qualitative text analysis to examine the relationship between three characteristics of network structure (degree centrality, network density, and betweenness centrality) and the progress of each QI initiative. RESULTS: The progress of QI initiatives varied considerably among organizations. The transition between stages was influenced by all three network characteristics to varying degrees, depending on the stage. Project managers whose QI initiatives progressed to advanced stages of implementation had formed ad hoc clusters of colleagues passionate about the initiatives. CONCLUSION: Implementing QI initiatives appears to be facilitated by the formation of clusters of supportive individuals within organizations; this formation requires high betweenness centrality and high network density. PRACTICE IMPLICATIONS: Flexibly modifying specific network characteristics depending on the stage of implementation may help project managers advance their QI initiatives, achieving more uniform results from QICs.

Factors driving differences in the adoption of quality management practices among hospitals: A two-phase, sequential mixed-methods analysis.

BACKGROUND: Although all hospitals aim to deliver high-quality care, there is considerable variation in their adoption of quality management (QM) practices. Organizational and environmental factors are known to drive strategic decision-making in hospitals, but their impact on the adoption of QM practices remains unclear. PURPOSE: Our study aims to identify multiple organizational and environmental factors that explain variation in the adoption of QM practices among hospitals and to explore mechanisms underlying these relationships. METHODOLOGY: We conducted a two-phase, sequential mixed-methods study of German acute care hospitals. The quantitative phase used between-effects regressions to identify factors explaining variation in the number of QM practices adopted by hospitals from 2015 to 2019. The qualitative phase used semistructured interviews with quality managers to gain in-depth insights. RESULTS: The number of QM practices adopted by a hospital was significantly associated with factors like hospital size and the presence of an emergency department or QM steering committee. Our qualitative findings highlighted potential mechanisms such as the presence of an emergency department serving as a proxy for organizational complexity or urgency of case-mix. CONCLUSION: We provide an overview of factors driving QM adoption in hospitals, extending beyond the focus on single factors in previous research. Future studies could explore additional factors highlighted by our interviewees. PRACTICE IMPLICATIONS: Our results can inform interventions to strengthen QM in hospitals and guide future research on this topic.

Exploring characteristics of specialization as moderators of the link between specialization and patient experience of care.

BACKGROUND: Hospitals are increasingly pursuing specialization as a strategy to operate efficiently while delivering high-quality care. To date, however, evidence is lacking on whether hospital specialization has a consistent effect on patients' experience of care or whether different specialization characteristics influence how specialization works. PURPOSE: This study investigates whether specialization characteristics, that is, the within-specialty concentration and the within-specialty urgency score, moderate the link between hospital specialization and patient experience of care. METHODOLOGY: We use patient-reported and administrative data from German hospitals between 2014 and 2017, with orthopedic and trauma care as the research setting. Our sample consists of 157,458 patient observations nested within 483 hospitals. We apply random-intercept multilevel modeling. RESULTS: Our results indicate that the effect of specialization on patient experience of care (a) decreases as the within-specialty concentration increases and (b) increases as the within-specialty urgency score increases. CONCLUSION: This study provides novel insights into the specialization characteristics that make hospital specialization in orthopedic and trauma care particularly effective at improving patient experiences. PRACTICE IMPLICATIONS: Although specialization is gaining popularity as a strategy for pooling scarce resources and facilitating high-quality health care, hospital managers and policymakers should consider that certain characteristics of specialization can influence the way that specialization works and how effective it is in improving patient experiences. Within the scope of orthopedic and trauma care, our study suggests that a low concentration of diagnoses within a service area and a high average level of medical urgency make specialization particularly effective at improving patient experiences.

Once is rarely enough: can social prescribing facilitate adherence to non-clinical community and voluntary sector health services? Empirical evidence from Germany.

BACKGROUND: Non-clinical health interventions provided by the voluntary and community sector can improve patients' health and well-being and reduce pressure on primary and secondary care, but only if patients adhere to them. This study provides novel insights into the impact of doctor referrals to such services, known as social prescribing, on patients' adherence to them. METHODS: Using a negative binomial model, we analysed electronic visitor records from a community health advice and navigation service in Germany between January 2018 and December 2019 to determine whether social prescribing was associated with greater adherence to the service (measured in terms of return visits) compared to patients who self-referred. We also explored whether this effect differed according to patient characteristics. RESULTS: Based on 1734 observations, we found that social prescribing was significantly associated with a greater number of return visits compared to patient self-referrals (p < 0.05). For patients who visited the service because of psychological concerns, the effect of social prescribing was lower. For all other patient characteristics, the effect remained unchanged, suggesting relevance to all other patient groups. CONCLUSIONS: The results of our study indicate that social prescribing may be an effective way to facilitate adherence to non-clinical community and voluntary sector health services. This knowledge is important for policy makers who are deciding whether to implement or expand upon social prescribing schemes.

Common and disease-specific dysfunctions of brain systems underlying attentional and executive control in schizophrenia and bipolar disorder.

Schizophrenia and bipolar disorder broadly overlap in multiple areas involving clinical phenomenology, genetics, and neurobiology. Still, the investigation into specific elementary (sub-)processes of executive functioning may help to define clear points of distinction between these categorical diagnoses to validate the nosological dichotomy and, indirectly, to further elucidate their pathophysiological underpinnings. In the present behavioral study, we sought to separate common from diagnosis-specific deficits in a series of specific elementary sub-functions of executive processing in patients with schizophrenia and bipolar disorder. For our purpose, we administered a modern and multi-purpose neuropsychological task paradigm to equal-sized and matched groups of schizophrenia patients, patients with bipolar disorder, and healthy control subjects. First, schizophrenia patients compared to the bipolar group exhibited a more pronounced deficit in general measures of task performance comprising both response speed and accuracy. Additionally, bipolar patients showed increased advance task preparation, i.e., were better able to compensate for response speed deficits when longer preparation intervals were provided. Set-shifting, on the other hand, was impaired to a similar degree in both patient groups. Finally, schizophrenia patients exhibited a specific deficit in conflict processing (inhibitory control) and the shielding of task-relevant processing from distraction (i.e., attentional maintenance). The present investigation suggests that specific neuropsychological measures of elementary executive functions may represent important points of dissociation between schizophrenia and bipolar disorder, which may help to differentiate the pathophysiological underpinnings of these major psychiatric disorders. In this context, the present findings highlight the measures of inhibitory control and attentional maintenance as promising candidates.

Which factors influence the decision of hospitals to provide procedures on an outpatient basis? -Mixed-methods evidence from Germany.

Shifting care from the resource-intensive inpatient setting to the more economically efficient outpatient sector is being promoted internationally by policymakers. Financial incentives are a major focus of such efforts because low levels of hospital outpatient care are attributed to differences in payment for inpatient and outpatient services. In Germany, however, there is significant variation in the extent to which hospitals provide outpatient care despite a uniform payment system. Therefore, other factors must be influencing German hospitals' strategic decisions whether to offer outpatient care. While most research has focused on specific procedures or lacks empirical support, our study provides a comprehensive analysis of the factors beyond financial incentives that influence the provision of hospital outpatient services in Germany. We employed a mixed-methods approach, first contacting health care experts with in-depth knowledge of the hospital outpatient landscape to identify possible influencing factors and then conducting a comprehensive quantitative analysis of all German hospitals. Our findings suggest that policymakers seeking to promote hospital outpatient care should consider a broad range of factors. We found that a hospital's service mix, size, procedure volume, and emergency care infrastructure significantly affected the proportion of outpatient services it offered. Strategic hospital planning emphasizing specialization and adherence to minimum volume standards might therefore be a valuable policy tool. Our analysis also highlights the importance of demographic and socioeconomic factors, such as the regional share of single-person households, suggesting that a comprehensive policy framework should account for broader population characteristics and not just elements directly related to hospital care.

Social connections at work and mental health during the first wave of the COVID-19 pandemic: Evidence from employees in Germany.

Empirical evidence on the social and psychological impact of the COVID-19 pandemic in the workplace and the resulting consequences for the mental health of employees is lacking. As a result, research on this subject is urgently needed to develop appropriate countermeasures. This study builds on Person-Environment fit theory to investigate social connections at work and mental health during the first wave of the COVID-19 pandemic. It analyses employees' needs for social connections and how social connections affect different mental health measures. Data were collected in May 2020 in an online survey of employees across Germany and analysed using response surface analysis. Mental health was measured as positive mental health and mental health disorders. Social connections were measured as social support and social interactions. 507 employees participated in the survey and more than one third reported having less social support and social interaction at work than they desired (p < .001). This was associated with a decrease in mental health. In contrast, having more than the desired amount of social support was associated with a decrease, and having more than the desired amount of social interaction with an increase, in mental health. This study provides important early evidence on the impact of the first wave of the COVID-19 pandemic in the workplace. With it, we aim to stimulate further research in the field and provide early evidence on the potential mental health consequences of social distancing-while also opening avenues to combat them.

Complex community health and social care interventions - Which features lead to reductions in hospitalizations for ambulatory care sensitive conditions? A systematic literature review.

Preventing hospitalizations due to ambulatory care sensitive conditions (ACSCs) is traditionally the responsibility of primary care. The determinants of ACSC hospitalizations, however, are not purely medical, but also influenced by other factors like patients' social and personal circumstances. Interventions that include or consist entirely of community health services and social care could potentially reduce the ACSC hospitalization rate. Comparisons of the features of successful interventions of this nature, however, are still lacking. We therefore conducted a systematic review of the literature to identify out-of-hospital interventions that (a) included aspects or consisted entirely of community health services and social care and (b) analyzed the ACSC hospitalization rate as an outcome measure. We identified papers reporting the results of 32 interventions and extracted structural and behavioral features to determine which of these were shared by most or all of the successful interventions. We found that all of the successful interventions included a primary care physician and provided care management. Moreover, most of the successful interventions were characterized by a high degree of interconnectedness between professional groups and provided care within so-called health care homes. We also identified a set of care coordination activities that were implemented in most of the successful interventions. Policy makers may wish to consider adopting these features when designing interventions that aim to reduce the ACSC hospitalization rate.

What is the impact of introducing a non-clinical community health advice and navigation service on the demand for primary care in socially deprived areas? Evidence from an observational panel study with difference-in-differences design.

OBJECTIVES: To examine the effect of introducing a non-clinical community health advice and navigation service on the demand for primary care in a socially deprived area. DESIGN: Observational panel study with difference-in-differences design. We conducted fixed-effects negative binomial regressions to compare changes in the number of visits to general practitioners (GPs) in individuals who visited the health advice and navigation service and a matched control group of individuals who did not visit the service. In addition, we analysed the effects of visiting the service multiple times. SETTING AND PARTICIPANTS: Our empirical setting is a socially deprived urban area in Germany with a multicultural population of about 110 000 people. Our analyses are based on patient data (N=1044) from a non-clinical community health advice and navigation service and from two statutory health insurers. OUTCOME MEASURES: Patient demand for primary care measured as the number of visits to GPs before and after the first visit to the health advice and navigation service. RESULTS: Visiting the service for the first time significantly decreased the number of GP visits compared with the control group (ß=-0.113, p<0.1). Each additional visit to the service, however, significantly decreased the effect of the first visit (ß=0.037, p<0.05). CONCLUSIONS: Our findings suggest that non-clinical community health advice and navigation services can serve as a low-threshold first point of contact. As first point contact, such services might possibly reduce the burden of primary care physicians in socially deprived areas. At the same time, such services might function as a gateway to accessing the health system, reducing unmet care needs and stimulate demand. Ongoing counselling in the service can identify medical needs that require a physician visit. Our findings may be useful for policymakers and healthcare leaders seeking to reduce the demand on the primary care workforce and can stimulate further research in this area.

Direct dating of Early Upper Palaeolithic human remains from Mladec.

The human fossil assemblage from the Mladec Caves in Moravia (Czech Republic) has been considered to derive from a middle or later phase of the Central European Aurignacian period on the basis of archaeological remains (a few stone artefacts and organic items such as bone points, awls, perforated teeth), despite questions of association between the human fossils and the archaeological materials and concerning the chronological implications of the limited archaeological remains. The morphological variability in the human assemblage, the presence of apparently archaic features in some specimens, and the assumed early date of the remains have made this fossil assemblage pivotal in assessments of modern human emergence within Europe. We present here the first successful direct accelerator mass spectrometry radiocarbon dating of five representative human fossils from the site. We selected sample materials from teeth and from one bone for 14C dating. The four tooth samples yielded uncalibrated ages of approximately 31,000 14C years before present, and the bone sample (an ulna) provided an uncertain more-recent age. These data are sufficient to confirm that the Mladec human assemblage is the oldest cranial, dental and postcranial assemblage of early modern humans in Europe and is therefore central to discussions of modern human emergence in the northwestern Old World and the fate of the Neanderthals.

Factors associated with patient activation in a socially deprived population: Evidence from Germany.

OBJECTIVE: Patient activation has been identified as a crucial determinant of health, but little is known about its own determinants, particularly in low socioeconomic status populations. To address this research gap, we analyzed factors that might explain variation in patient activation in such a population. METHODS: We conducted a cross-sectional patient survey (n = 582) in a low socioeconomic status urban district in Germany in 2017. Using multivariate linear regressions, we examined the association between patient activation and a range of psychological, sociodemographic, and health-related factors. To assess the relative importance of these factors, we used dominance analysis. RESULTS: Our results suggest that age, employment status, linguistic acculturation, health status, and self-efficacy were significantly associated with patient activation. Dominance analysis indicated that self-efficacy was the most important factor explaining variation in patient activation. CONCLUSIONS: Age, employment status, linguistic acculturation, health status, and self-efficacy are important determinants of patient activation. PRACTICE IMPLICATIONS: Our results can inform decision makers about approaches for more targeted and effective interventions to improve patient activation in low socioeconomic status populations. Much might be gained by investing in interventions that focus on age, employment status, linguistic acculturation, and health status. Interventions that improve self-efficacy may represent a particularly promising approach.

Explaining variation in health information seeking behaviour - Insights from a multilingual survey.

OBJECTIVE: How best to provide an increasingly diverse population with health information has become a major concern for health policy makers in Europe and beyond. Our study aims to investigate factors explaining variation in people's health information seeking behaviour. Our findings can be used to identify target groups for policy interventions that aim to provide health information efficiently. METHODS: Cross-sectional, paper-based, multilingual survey of a random sample of enrolees of two statutory health insurers in Hamburg, Germany. Data were collected from September to December 2017. Multivariable logistic regression was used to examine sociodemographic and health-related individual characteristics and their associations with participants' choice of ten sources of health information. FINDINGS: Participants' choice of information sources differed significantly across the following sociodemographic and health-related characteristics: age, gender, immigration status, education, employment status, marital status and general state of health. Immigrants and individuals with low educational attainment were most likely to use emergency departments as sources of health information. CONCLUSION: Policy interventions aiming to manage the use of health information sources should focus on immigrants and individuals with low educational attainment. Providing multilingual, low-threshold counselling and information services could be an efficient way to reduce short-term costs of health information seeking behaviour to health insurers or other payers of care while improving patient empowerment.

Revisiting the Middle and Upper Palaeolithic archaeology of Gruta do Caldeirão (Tomar, Portugal).

Gruta do Caldeirão features a c. 6 m-thick archaeological stratification capped by Holocene layers ABC-D and Ea, which overlie layer Eb, a deposit of Magdalenian age that underwent significant disturbance, intrusion, and component mixing caused by funerary use of the cave during the Early Neolithic. Here, we provide an updated overview of the stratigraphy and archaeological content of the underlying Pleistocene succession, whose chronology we refine using radiocarbon and single-grain optically stimulated luminescence dating. We find a high degree of stratigraphic integrity. Dating anomalies exist in association with the succession's two major discontinuities: between layer Eb and Upper Solutrean layer Fa, and between Early Upper Palaeolithic layer K and Middle Palaeolithic layer L. Mostly, the anomalies consist of older-than-expected radiocarbon ages and can be explained by bioturbation and palimpsest-forming sedimentation hiatuses. Combined with palaeoenvironmental inferences derived from magnetic susceptibility analyses, the dating shows that sedimentation rates varied in tandem with the oscillations in global climate revealed by the Greenland oxygen isotope record. A steep increase in sedimentation rate is observed through the Last Glacial Maximum, resulting in a c. 1.5 m-thick accumulation containing conspicuous remains of occupation by people of the Solutrean technocomplex, whose traditional subdivision is corroborated: the index fossils appear in the expected stratigraphic order; the diagnostics of the Protosolutrean and the Lower Solutrean predate 24,000 years ago; and the constraints on the Upper Solutrean place it after Greenland Interstadial 2.2. (23,220-23,340 years ago). Human usage of the site during the Early Upper and the Middle Palaeolithic is episodic and low-intensity: stone tools are few, and the faunal remains relate to carnivore activity. The Middle Palaeolithic is found to persist beyond 39,000 years ago, at least three millennia longer than in the Franco-Cantabrian region. This conclusion is upheld by Bayesian modelling and stands even if the radiocarbon ages for the Middle Palaeolithic levels are removed from consideration (on account of observed inversions and the method's potential for underestimation when used close to its limit of applicability). A number of localities in Spain and Portugal reveal a similar persistence pattern. The key evidence comes from high-resolution fluviatile contexts spared by the site formation issues that our study of Caldeirão brings to light-palimpsest formation, post-depositional disturbance, and erosion. These processes. are ubiquitous in the cave and rock-shelter sites of Iberia, reflecting the impact on karst archives of the variation in climate and environments that occurred through the Upper Pleistocene, and especially at two key points in time: between 37,000 and 42,000 years ago, and after the Last Glacial Maximum. Such empirical difficulties go a long way towards explaining the controversies surrounding the associated cultural transitions: from the Middle to the Upper Palaeolithic, and from the Solutrean to the Magdalenian. Alongside potential dating error caused by incomplete decontamination, proper consideration of sample association issues is required if we are ever to fully understand what happened with the human settlement of Iberia during these critical intervals, and especially so with regards to the fate of Iberia's last Neandertal populations.

The increase of soil organic carbon as proposed by the "4/1000 initiative" is strongly limited by the status of soil development - A case study along a substrate age gradient in Central Europe.

During COP 21 in Paris 2015, several states and organizations agreed on the "4/1000" initiative for food security and climate. This initiative aims to increase world's soil organic carbon (SOC) stocks by 4‰ annually. The influence of soil development status on SOC dynamics is very important but usually not considered in studies. We analyse SOC accumulation under forest, grassland and cropping systems along a soil age gradient (10-17,000years) to show the influence of soil development status on SOC increase. SOC stocks (0-40cm) and accumulation rates along a chronosequence in alluvial soils of the Danube River in the Marchfeld (eastern Austria) were analysed. The analysed Fluvisols and Chernozems have been used as forest, grassland and cropland for decades or hundreds of years. The results showed that there is a fast build-up of OC stocks (0-40cm) in young soils with accumulation of ~1.3tha-1a-1 OC in the first 100years and ~0.5tha-1a-1 OC between 100 and 350years almost independent of land use. Chernozems with a sediment deposition age older than 5.000years have an accumulation rate<0.01tOCha-1a-1 (0-40cm). Radiocarbon dating showed that the topsoil (0-10cm) consists mainly of ">modern" and "modern" carbon indicating a fast carbon cycling. Carbon in subsoil is less exposed to decomposition and OC can be stored at long-time scales in the subsoil (14C age of 3670±35 BP). In view of the '4/1000' initiative, soils with constant carbon input (forest & grassland) fulfil the intended 4‰ growth rate of SOC stocks only in the first 60years of soil development. We proclaim that under the present climate in Central Europe, the increase of SOC stocks in soil is strongly affected by the state of soil development.

Radiocarbon re-dating of contact-era Iroquoian history in northeastern North America.

A time frame for late Iroquoian prehistory is firmly established on the basis of the presence/absence of European trade goods and other archeological indicators. However, independent dating evidence is lacking. We use 86 radiocarbon measurements to test and (re)define existing chronological understanding. Warminster, often associated with Cahiagué visited by S. de Champlain in 1615-1616 CE, yields a compatible radiocarbon-based age. However, a well-known late prehistoric site sequence in southern Ontario, Draper-Spang-Mantle, usually dated ~1450-1550, yields much later radiocarbon-based dates of ~1530-1615. The revised time frame dramatically rewrites 16th-century contact-era history in this region. Key processes of violent conflict, community coalescence, and the introduction of European goods all happened much later and more rapidly than previously assumed. Our results suggest the need to reconsider current understandings of contact-era dynamics across northeastern North America.

Precise dating of the Middle-to-Upper Paleolithic transition in Murcia (Spain) supports late Neandertal persistence in Iberia.

The late persistence in Southern Iberia of a Neandertal-associated Middle Paleolithic is supported by the archeological stratigraphy and the radiocarbon and luminescence dating of three newly excavated localities in the Mula basin of Murcia (Spain). At Cueva Antón, Mousterian layer I-k can be no more than 37,100 years-old. At La Boja, the basal Aurignacian can be no less than 36,500 years-old. The regional Middle-to-Upper Paleolithic transition process is thereby bounded to the first half of the 37th millennium Before Present, in agreement with evidence from Andalusia, Gibraltar and Portugal. This chronology represents a lag of minimally 3000 years with the rest of Europe, where that transition and the associated process of Neandertal/modern human admixture took place between 40,000 and 42,000 years ago. The lag implies the presence of an effective barrier to migration and diffusion across the Ebro river depression, which, based on available paleoenvironmental indicators, would at that time have represented a major biogeographical divide. In addition, (a) the Phlegraean Fields caldera explosion, which occurred 39,850 years ago, would have stalled the Neandertal/modern human admixture front because of the population sink it generated in Central and Eastern Europe, and (b) the long period of ameliorated climate that came soon after (Greenland Interstadial 8, during which forests underwent a marked expansion in Iberian regions south of 40°N) would have enhanced the "Ebro Frontier" effect. These findings have two broader paleoanthropological implications: firstly, that, below the Ebro, the archeological record made prior to 37,000 years ago must be attributed, in all its aspects and components, to the Neandertals (or their ancestors); secondly, that modern human emergence is best seen as an uneven, punctuated process during which long-lasting barriers to gene flow and cultural diffusion could have existed across rather short distances, with attendant consequences for ancient genetics and models of human population history.