Estimating incident population distribution from prevalent data

A prevalent sample consists of individuals who have experienced disease incidence but not failure event at the sampling time. We discuss methods for estimating the distribution function of a random vector defined at baseline for an incident disease population when data are collected by prevalent sampling. Prevalent sampling design is often more focused and economical than incident study design for studying the survival distribution of a diseased population, but prevalent samples are biased by design. Subjects with longer survival time are more likely to be included in a prevalent cohort, and other baseline variables of interests that are correlated with survival time are also subject to sampling bias induced by the prevalent sampling scheme. Without recognition of the bias, applying empirical distribution function to estimate the population distribution of baseline variables can lead to serious bias. In this article, nonparametric and semiparametric methods are developed for distribution estimation of baseline variables using prevalent data.     

Monte Carlo uncertainty analysis of dose estimates in radiochromic film dosimetry with single-channel and multichannel algorithms

PurposeTo provide a multi-stage model to calculate uncertainty in radiochromic film dosimetry with Monte-Carlo techniques. This new approach is applied to single-channel and multichannel algorithms.Material and methodsTwo lots of Gafchromic EBT3 are exposed in two different Varian linacs. They are read with an EPSON V800 flatbed scanner. The Monte-Carlo techniques in uncertainty analysis provide a numerical representation of the probability density functions of the output magnitudes. From this numerical representation, traditional parameters of uncertainty analysis as the standard deviations and bias are calculated. Moreover, these numerical representations are used to investigate the shape of the probability density functions of the output magnitudes. Also, another calibration film is read in four EPSON scanners (two V800 and two 10000XL) and the uncertainty analysis is carried out with the four images.ResultsThe dose estimates of single-channel and multichannel algorithms show a Gaussian behavior and low bias. The multichannel algorithms lead to less uncertainty in the final dose estimates when the EPSON V800 is employed as reading device. In the case of the EPSON 10000XL, the single-channel algorithms provide less uncertainty in the dose estimates for doses higher than four Gy.ConclusionA multi-stage model has been presented. With the aid of this model and the use of the Monte-Carlo techniques, the uncertainty of dose estimates for single-channel and multichannel algorithms are estimated. The application of the model together with Monte-Carlo techniques leads to a complete characterization of the uncertainties in radiochromic film dosimetry.     

Declining hysterectomy prevalence and the estimated impact on uterine cancer incidence in Scotland

AimThe prevalence of hysterectomy is decreasing worldwide. It is not clear whether changes in the population at risk (women with intact uteruses) have contributed to an increased uterine cancer incidence. This study aims to assess the effect of changing trends in hysterectomy prevalence on uterine cancer incidence in Scotland.MethodsThe population of women aged ≥25 years with intact uteri was estimated using the estimated hysterectomy prevalence in 1995 and the number of procedures performed in Scotland (1996–2015). Age-standardized uterine cancer incidence was estimated using uncorrected (total) or corrected (adjusted for hysterectomy prevalence) populations as denominators and the number of incident cancers as numerators. Annual percentage change in uterine cancer was estimated.ResultsHysterectomy prevalence fell from 13% to 10% between 1996–2000 and 2011–2015, with the most marked decline (from 20% to 6%) in the 50–54-year age group. After correction for hysterectomy prevalence, age-standardized incidence of uterine cancer increased by 20–22%. Annual percentage change in incidence of uterine cancer remained stable through the study period and was 2.2% (95%CI 1.8–2.7) and 2.1% (95%CI 1.7–2.6) for uncorrected and corrected estimates, respectively.ConclusionUterine cancer incidence in Scotland corrected for hysterectomy prevalence is higher than estimates using a total female population as denominator. The annual percentage increase in uterine cancer incidence was stable in both uncorrected and corrected populations despite a declining hysterectomy prevalence. The rise in uterine cancer incidence may thus be driven by other factors, including an ageing population, changing reproductive choices, and obesity.     

Burden of cancer attributable to tobacco smoking in member countries of the Association of Southeast Asian Nations (ASEAN), 2012

BackgroundCancer is an increasing problem in ASEAN (Association of Southeast Asian Nations). Tobacco use is a well-established risk factor for many types of cancers. Evidence on burden of cancer attributable to tobacco is essential to raise public and political awareness of the negative effects of tobacco on cancer and to be used to stimulate political action aims at reducing smoking prevalence in ASEAN member countries. The objective of this study was to estimate burden of cancer attributable to tobacco smoking in ASEAN, 2012.MethodsIn this study, smoking prevalence was combined with Relative Risks (RRs) of cancer to obtain Smoking Attributable Fractions (SAFs). Cancer incidence and mortality data among individuals aged 15 years and older were derived from GLOBOCAN 2012. Fourteen types of cancer were included in the analysis. Sensitivity analyses were conducted to examine the impact of the use of alternative RRs and the use of alternative prevalence of smoking in some countries.ResultsThe findings showed that tobacco smoking was responsible for 131,502 cancer incidence and 105,830 cancer mortality in ASEAN countries in 2012. In other words, tobacco smoking was accounted for 28.4% (43.3% in male and 8.5% in female) of cancer incidence and 30.5% (44.2% in male and 9.4% in female) of cancer mortality in ASEAN. When looking at the types of cancer, lung cancer showed the strongest association with tobacco smoking. Incidence of cancer and cancer mortality attributable to tobacco smoking varied by countries due to the differences in size of population, background risk of cancer, and prevalence of smoking in each country. According to the sensitivity analyses, RRs of lung cancer, pharynx cancer, and larynx cancer used in the estimates have significant impact on the estimates.ConclusionsAs about one-third of cancer incidence and mortality in ASEAN are attributable to tobacco smoking ASEAN member countries are strongly encouraged to put in place stronger tobacco control policies and to strengthen the existing tobacco control measure in order to effectively control cancer.     

Measurement error and survey design in sightability model development

Measurement error of explanatory variables used in sightability models can result in biased population estimates and associated measures of precision. We developed a Monte Carlo simulation procedure that can be implemented within the sightability model framework when measurement error is present. Additionally, we developed simulation and sample survey methods, for determining the optimal allocation of survey effort to maximize precision of population estimates for a fixed survey cost, when a complete survey of a study area is not feasible. We used data from aerial surveys of elk during 2004–2006 in Michigan to demonstrate the application of these techniques. By accounting for measurement error and applying appropriate survey design practices, managers employing sightability models may be able to generate more accurate and cost-effective population estimates and accompanying measures of precision than is possible if these techniques are ignored. © 2011 The Wildlife Society.     

The completeness and timeliness of cancer registration and the implications for measuring cancer burden

BackgroundPopulation based cancer registration provides a critical role in disease surveillance in terms of incidence, survival, cancer cluster investigations and prevalence trends, and therefore high levels of completeness and timeliness are required. This study estimates completeness and variation between early and late registrations in the N. Ireland Cancer Registry (NICR) and assesses the implications for reporting cancer incidence and for registry-based research.MethodsTwo main approaches assessed completeness. For the period 2010–2012, incidence reported in the first year of data publication was compared to incidence reported in subsequent years until 2015. Demographic characteristics and survival of incident cases ascertained before the first publication year were compared to those ascertained in subsequent years. The flow method approach was used to estimate completeness annually after the incident year.ResultsOverall incidence for all cancers increased between the first year of data publication and subsequent years up to 2015, irrespective of year of diagnosis. Late registrations had poorer survival. The flow method approach estimated the completeness of case ascertainment of NICR data to be 96% complete at five years for all cancers combined.ConclusionThe estimated completeness levels for the NICR are comparable to other high quality cancer registries internationally. While data timeliness has little impact on incidence estimates, delays in registration may have implications for specific research studies into incidence and survival. This means that improvements in the timeliness of reporting should be a target for all registries but not at the expense of completeness.     

Estimation of Incidence from Age Wise Prevalence

A method used by various researchers for estimation of incidence from prevalence data of a stable population for irreversible stable diseases has been validated. For this purpose a followup data was generated by life table distribution techniques with known mortality and incidence rates. The results show that the method as such cannot be used to estimate the true incidence from prevalence data of a crossectional study from stable population. The remote situation where the method will work has been discussed. A method has also been presented for situations where the known method fails i.e. duration of irreversible disease is less than the age of effected persons in a stable population.     

Parameter identification in epidemic models

Starting from a recent paper of Pollicott, Wang and Weiss we try to obtain improved representation formulas for the estimation of the time-dependent transmission rate of an epidemic in terms of either incidence or prevalence data. Although the formulas are (trivially) mathematically equivalent to previous formulas, the new representations need no additional estimates and they should be more stable numerically.We review the discrete time and the stochastic continuous time approach. We replace the assumption that recovery follows an exponential distribution and get estimates for the transmission rate for constant duration of the infectious phase.     

Methodological aspects of estimating rare cancer prevalence in Europe: The experience of the RARECARE project

This paper describes the usage and the performance evaluation of the completeness index method in the ‘Surveillance of Rare Cancers in Europe project’ (RARECARE) for estimating rare cancer prevalence in Europe. The 15-year prevalence at 1st January 2003 for 255 cancers is obtained from a pool of 22 RARECARE cancer registries (CRs). Incidence and survival models are applied to the RARECARE database to estimate the parameters from which the completeness indices are calculated. Complete prevalence is obtained adjusting the observed 15-year prevalence by the completeness index, to account for those cancer survivors diagnosed before the CR activity started. Main factors influencing the performance of the completeness index method for rare cancers are the same as for common cancers: age distribution of incidence and lethality of the cancer. For cancers occurring in the elderly, with low survival rates and consequently a restricted number of long-term survivors we obtained completeness indices higher than 0.9. Values lower than 0.7 correspond to those cancers with good prognosis and/or incidence more concentrated at the younger ages, indicating that 15 years of follow up are insufficient to detect all prevalent cases. Validation analysis shows that for a restricted subgroup of rare cancers with very low incidence and low survival, the completeness indices were not able to adequately correct the observed prevalence even considering a registration period of 20 years. On average, sensitivity analyses show a slight overestimation of complete prevalence for rare and common cancers whose increasing incidence is known in literature. RARECARE is the largest project on rare cancers conducted to date. Improving health care programs for cancer survivors is a public health priority and prevalence data which provides important information in this field should be regularly asked to Member States and included in the EU health statistics.     

Investigating prevalence of dental anomalies in Eastern Province of Saudi Arabia through digital orthopantomogram

ObjectiveThe aim of this study was to investigate the prevalence of dental anomalies in the Eastern Province of Saudi Arabia using the digital Orthopantomography (OPG).MethodsA retrospective radiographic study was performed in which digital OPGs of 1189 subjects, ages ranging between 7 and 65 years were reviewed, and 1104 fulfilled inclusion criteria. Statistical analysis was performed. The OPGs were reviewed for congenitally missing teeth, impactions, ectopic eruption, supernumerary teeth, odontomas, dilacerations, taurodontism, dens in dente, gemination and fusion.ResultsOPGs of 1104 patients with mean age 35.32 ± 16.63 were included. The total prevalence of developmental anomalies in this study was 36.3% (401/1104). Male and female subjects with anomalies were 133 (33.2%) and 268 (66.8%) respectively. The prevalence of dilacerated teeth 300 (30.2%), congenitally missing teeth was 246 (24.7%), supernumerary teeth 18 (1.8%), talon cusp and taurodontism were seen in one patient each 1 (0.1%). Of these, a total of 15 (1.5%) anomalies were noted in pediatric patients.ConclusionsDilaceration was the most prevalent anomaly (30.2%) in the studied sample followed by congenitally missing teeth (23.4%). Talon cusp, concrescence/fusion, and taurodontism were the least prevalent anomalies.     

Seven years prevalence and distribution of high and low risk HPV genotypes in women living in the metropolitan area of Naples

BackgroundThe objective of this work was to provide an update information on HPV age/genotype distribution by retrospectively analyzing a cohort of women living in the metropolitan area of Naples.MethodsFrom January 2011 to December 2017, cervical scrape specimens from 1265 women, with abnormal cytological indication, were tested for HPV DNA. The presence and the viral genotypes were assessed by the Linear Array HPV genotyping test for the detection of 37 anogenital HPV-DNA genotypes.ResultsThe overall prevalence of HPV infections was of 44.5% (95% CI 41.77–47.24). Among HR-HPV types, HPV-16 was the most common identified genotype, followed by HPV-31, -66, -59 and -51. As concern LR-HPV, HPV-53 resulted the most prevalent. Stratifying the study population by age, the total HPV infections showed a peak in younger women aged <23 years (58.5%), with a significative decrease by age (23–29 years, 54%; ≥ 30 years, 38.2%) (p < 0.001).ConclusionWe provided an HPV epidemiological analysis, highlighting the need to implement vaccination programmes and preventative screening strategies.     

Impact of variation in cancer registration practice on observed international cancer survival differences between International Cancer Benchmarking Partnership (ICBP) jurisdictions

BackgroundInternational cancer survival comparisons use cancer registration data to report cancer survival, which informs the development of cancer policy and practice. Studies like the International Cancer Benchmarking Partnership (ICBP) have a duty to understand how registration differences impact on survival prior to drawing conclusions.MethodsKey informants reported differences in registration practice for capturing incidence date, death certificate case handling and registration of multiple primary tumours. Sensitivity analyses estimated their impact on one-year survival using baseline and supplementary cancer registration data from England and Sweden.ResultsVariations in registration practice accounted for up to a 7.3 percentage point difference between unadjusted (estimates from previous ICBP survival data) and adjusted (estimates recalculated accounting for registration differences) one-year survival, depending on tumour site and jurisdiction.One-year survival estimates for four jurisdictions were affected by adjustment: New South Wales, Norway, Ontario, Sweden. Sweden and Ontario’s survival reduced after adjustment, yet they remained the jurisdictions with the highest survival for breast and ovarian cancer respectively. Sweden had the highest unadjusted lung cancer survival of 43.6% which was adjusted to 39.0% leaving Victoria and Manitoba with the highest estimate at 42.7%. For colorectal cancer, Victoria’s highest survival of 85.1% remained unchanged after adjustment.ConclusionPopulation-based cancer survival comparisons can be subject to registration biases that may impact the reported ‘survival gap’ between populations. Efforts should be made to apply consistent registration practices internationally. In the meantime, survival comparison studies should provide acknowledgement of or adjustment for the registration biases that may affect their conclusions.     

Prevalence and incidence of young onset dementia and associations with comorbidities: A study of data from the French national health data system

BackgroundDementia onset in those aged <65 years (young onset dementia, YOD) has dramatic individual and societal consequences. In the context of population aging, data on YOD are of major importance to anticipate needs for planning and allocation of health and social resources. Few studies have provided precise frequency estimates of YOD. The aim of this study is to provide YOD prevalence and incidence estimates in France and to study the contribution of comorbidities to YOD incidence.Methods and findingsUsing data from the French national health data system (Système National des Données de Santé, SNDS) for 76% of the French population aged 40 to 64 years in 2016 (n = 16,665,795), we identified all persons with dementia based on at least 1 of 3 criteria: anti-Alzheimer drugs claims, hospitalization with the International Classification of Diseases-10th Revision (ICD-10) dementia codes (F00 to F03, G30, G31.0, G31.1, or F05.1), or registration for free healthcare for dementia. We estimated prevalence rate (PR) and incidence rate (IR) and estimated the association of comorbidities with incident YOD. Sex differences were investigated. We identified 18,466 (PR_standardized = 109.7/100,000) and 4,074 incident (IR_standardized = 24.4/100,000 person-years) persons with prevalent and incident YOD, respectively. PR and IR sharply increased with age. Age-adjusted PR and IR were 33% (95% confidence interval (CI) = 29 to 37) and 39% (95% CI = 31 to 48) higher in men than women (p < 0.001 both for PR and IR). Cardio- and cerebrovascular, neurological, psychiatric diseases, and traumatic brain injury prevalence were associated with incident YOD (age- and sex-adjusted p-values <0.001 for all comorbidities examined, except p = 0.109 for antihypertensive drug therapy). Adjustment for all comorbidities explained more than 55% of the sex difference in YOD incidence. The lack of information regarding dementia subtypes is the main limitation of this study.ConclusionsWe estimated that there were approximately 24,000 and approximately 5,300 persons with prevalent and incident YOD, respectively, in France in 2016. The higher YOD frequency in men may be partly explained by higher prevalence of cardiovascular and neurovascular diseases, substance abuse disorders, and traumatic brain injury and warrants further investigation.

In an observational study, Laure Carcaillon-Bentata and colleagues investigate the prevalence and incidence of dementia onset among adults younger than 65 years of age using data from the French national health data system from 2016.     

The burden of squamous cell carcinoma of the conjunctiva in Africa

Squamous cell carcinoma of the conjunctiva (SCCC) is a relatively common cancer in Africa, although its precise incidence and geographic distribution have not been previously systematically studied.MethodsUsing the methods employed to produce national estimates of cancer incidence for the “Globocan” series of the International Agency for Research on Cancer, along with detailed information on cancer incidence by histological subtype from cancer registries in Africa, we estimate the numbers and rates of incidence by sex, age group, country and region of Africa.ResultsWe estimate that the number of new cases occurring in 2018 to be about 6 200, with all but about 50 in sub Saharan Africa, and 55% in females.On a national basis, the geographic distribution of incidence rates resembles that of the prevalence of infection with HIV, with a strong correlation between them, especially in males.ConclusionsWe estimate that about one third of the total cases of SCCC occurring in Africa are HIV-related.     

A retrospective analysis of human papillomavirus (HPV) prevalence and genotype distribution among 25,238 women in Shanghai,China revealed the limitations of current HPV-based screening and HPV vaccine

BackgroundTo determine the human papillomavirus (HPV) type-specific prevalence and distribution among women with various age and cervical lesions in Shanghai, China. And to evaluate the carcinogenicity of different high-risk HPV (HR-HPV) and the efficacy of HR-HPV testing and HPV vaccine.MethodsThe clinical data from 25,238 participants who received HR-HPV testing (HPV GenoArray test kit, HybriBio Ltd) at the Affiliated Hospital of Tongji University from 2016 to 2019 were reviewed and analyzed using SPSS (version 20.0, Tongji University, China).ResultsThe overall prevalence of HPV was 45.57% in the study population, of which 93.51% were found HR-HPV infection. The three most prevalent HR-HPV genotypes were HPV 52 (22.47%), 16 (16.4%) and 58 (15.93%) among HPV-positive women, and HPV 16 (43.30%), 18 (9.28%) and 58 (7.22%) in women with histologically confirmed cervical cancer (CC). 8.25% of CC were found to be HPV negative. Only 83.51% of CC cases were related to the HPV genotypes covered by nine-valent HPV vaccine. HPV prevalence and genotype distribution varied with age and cervical histology. The odds ratios (OR) of HR-HPV for CC were also different, among which the top three types were HPV 45 [OR= 40.13, 95% confidence intervals (CI) 10.37–155.38], 16 (OR=33.98, 95%CI 15.90–72.60) and 18 (OR=21.11, 95%CI 8.09–55.09). The increase in the types of HPV infection did not increase the risk of CC correspondingly. As the primary cervical screening method, HR-HPV testing showed the high sensitivity (93.97%, 95%CI 92.00–95.49) but low specificity (42.82%, 95%CI 41.81–43.84).ConclusionsOur study provide the comprehensive epidemiological data on HPV prevalence and genotype distribution among Shanghai women with various cervical histology, which can not only serve as a significant reference for clinical practice, but also implicated the need of more effective CC screening methods and HPV vaccine covering more subtypes.     

Disease Burden of 32 Infectious Diseases in the Netherlands, 2007-2011

BackgroundInfectious disease burden estimates provided by a composite health measure give a balanced view of the true impact of a disease on a population, allowing the relative impact of diseases that differ in severity and mortality to be monitored over time. This article presents the first national disease burden estimates for a comprehensive set of 32 infectious diseases in the Netherlands.ConclusionsFor guiding and supporting public health policy decisions regarding the prioritisation of interventions and preventive measures, estimates of disease burden and the comparison of burden between diseases can be informative. Although the collection of disease-specific parameters and estimation of incidence is a process subject to continuous improvement, the current study established a baseline for assessing the impact of future public health initiatives.     

Methodological variance associated with normalization of occupational upper trapezius EMG using sub-maximal reference contractions

ObjectivesTo quantify the variance introduced to trapezius electromyography (EMG) through normalization by sub-maximal reference voluntary exertions (RVE), and to investigate the effect of increased normalization efforts as compared to other changes in data collection strategy on the precision of occupational EMG estimates.MethodsWomen performed four RVE contractions followed by 30 min of light, cyclic assembly work on each of two days. Work cycle EMG was normalized to each of the RVE trials and seven exposure parameters calculated. The proportions of exposure variance attributable to subject, day within subject, and cycle and normalization trial within day were determined. Using this data, the effect on the precision of the exposure mean of altering the number of subjects, days, cycles and RVEs during data collection was simulated.ResultsFor all exposure parameters a unique component of variance due to normalization was present, yet small: less than 4.4% of the total variance. The resource allocation simulations indicated that marginal improvements in the precision of a group exposure mean would occur above three RVE repeats for EMG collected on one day, or beyond two RVEs for EMG collected on two or more days.     

Disparate data streams together yield novel survival estimates of Alaska-breeding Whimbrels

Survival estimates are critical components of avian ecology. In well-intentioned efforts to maximize the utility of one's research, survival estimates often derive from data that were not originally collected for survival assessments, and such post hoc analyses may include unintentional biases. We estimated the survival of Whimbrels captured and marked at two breeding sites in Alaska using divergent data streams that in isolation were subject to methodological biases. Although both capture sites were chosen to study the migration ecology of Alaska-breeding Whimbrels, maximizing the conservation value of the data we collected was obviously desirable. We used multi-year telemetry information to infer survival from one site (Colville River) and mark–resight techniques to estimate survival from a second site (Kanuti River). At Colville River, we could not feasibly include a control group of birds to assess potential survival effects of externally mounted transmitters, and at Kanuti River we were unable to account accurately for potential emigration events because we used resightings alone. We integrated these datasets in a Bayesian hierarchical framework, an approach that permitted insights across sites that moderated methodological biases within sites. Using telemetry enabled us to detect permanent emigration events from breeding sites in two of 10 birds, results that informed estimates for birds without tracking devices. These datasets yielded point estimates of true survival of Whimbrels from Colville River equipped with solar-powered satellite transmitters that were higher (0.83) than true survival estimates of Whimbrels from Kanuti River marked with leg flags alone (0.74) or equipped with surgically implanted satellite transmitters (0.50), but the 95% credible intervals on these estimates overlapped across groups. For species such as Whimbrels that are difficult and costly to study, combining information from disparate data streams allowed us to derive novel demographic estimates, an approach with clear application to other similar studies.     

Estimating incidence from prevalence in generalised HIV epidemics: methods and validation

Background

HIV surveillance of generalised epidemics in Africa primarily relies on prevalence at antenatal clinics, but estimates of incidence in the general population would be more useful. Repeated cross-sectional measures of HIV prevalence are now becoming available for general populations in many countries, and we aim to develop and validate methods that use these data to estimate HIV incidence.

Methods and Findings

Two methods were developed that decompose observed changes in prevalence between two serosurveys into the contributions of new infections and mortality. Method 1 uses cohort mortality rates, and method 2 uses information on survival after infection. The performance of these two methods was assessed using simulated data from a mathematical model and actual data from three community-based cohort studies in Africa. Comparison with simulated data indicated that these methods can accurately estimates incidence rates and changes in incidence in a variety of epidemic conditions. Method 1 is simple to implement but relies on locally appropriate mortality data, whilst method 2 can make use of the same survival distribution in a wide range of scenarios. The estimates from both methods are within the 95% confidence intervals of almost all actual measurements of HIV incidence in adults and young people, and the patterns of incidence over age are correctly captured.

Conclusions

It is possible to estimate incidence from cross-sectional prevalence data with sufficient accuracy to monitor the HIV epidemic. Although these methods will theoretically work in any context, we have able to test them only in southern and eastern Africa, where HIV epidemics are mature and generalised. The choice of method will depend on the local availability of HIV mortality data.     

Using incidental mark‐encounter data to improve survival estimation

1. Obtaining robust survival estimates is critical, but sample size limitations often result in imprecise estimates or the failure to obtain estimates for population subgroups. Concurrently, data are often recorded on incidental reencounters of marked individuals, but these incidental data are often unused in survival analyses.
2. We evaluated the utility of supplementing a traditional survival dataset with incidental data on marked individuals that were collected ad hoc. We used a continuous time‐to‐event exponential survival model to leverage the matching information contained in both datasets and assessed differences in survival among adult and juvenile and resident and translocated Mojave desert tortoises (Gopherus agassizii).
3. Incorporation of the incidental mark‐encounter data improved precision of all annual survival point estimates, with a 3.4%–37.5% reduction in the spread of the 95% Bayesian credible intervals. We were able to estimate annual survival for three subgroup combinations that were previously inestimable. Point estimates between the radiotelemetry and combined datasets were within |0.029| percentage points of each other, suggesting minimal to no bias induced by the incidental data.
4. Annual survival rates were high (>0.89) for resident adult and juvenile tortoises in both study sites and for translocated adults in the southern site. Annual survival rates for translocated juveniles at both sites and translocated adults in the northern site were between 0.73 and 0.76. At both sites, translocated adults and juveniles had significantly lower survival than resident adults. High mortality in the northern site was driven primarily by a single pulse in mortalities.
5. Using exponential survival models to leverage matching information across traditional survival studies and incidental data on marked individuals may serve as a useful tool to improve the precision and estimability of survival rates. This can improve the efficacy of understanding basic population ecology and population monitoring for imperiled species.