Sources Of Error Research Articles

Treatment experiences and decision-making among patients with metastatic colorectal cancer: Results of an online US patient survey.

80 Background: Developing treatment plans for patients (pts) with metastatic colorectal cancer (mCRC) is complex. Using an online survey, we aimed to understand the treatment experience of pts with mCRC, including pt involvement in treatment decision-making. Methods: Adults (≥18 yrs) with mCRC took part in an online survey conducted in the US by The Harris Poll between Jan 17 and Feb 7, 2024. Of 344 respondents, 90 were recruited from patient advocacy groups (PAGs). The 60-question survey explored pts’ experience of mCRC. We report results from questions focused on treatment. Raw data were not weighted and are only representative of the participants. All surveys are subject to sources of error. Results: Of 256/344 pts who received mCRC treatment, chemotherapy and surgery were the most common therapies(Table). Among pts who received therapy, 67% reported their ability to take treatment was impacted by non-medical factors such as finances or mental health. Overall, 58% of pts have had to decide between affording treatment or meeting basic needs, e.g. safe housing, food, transportation, especially Black and Hispanic pts (Table). Of all 344 pts, 87% reported reliance on their healthcare provider (HCP) when making treatment decisions, primarily their oncology surgeon (48%) or oncologist (45%), despite 268 (78%) pts carrying out independent research on new treatments or clinical trials. Although 266 pts (77%) were involved in treatment decision making, 231 pts (67%) wished for more power in the process. Overall, 64 pts (19%) wished for more support from PAGs during treatment, while 59 pts (17%) relied on PAGs to help guide treatment decisions. The most common factors affecting pt treatment decisions related to costs or insurance coverage (52%), impacts on physical health and quality of life (each 39%), fear of being a burden on family (35%), and side effects (32%). Conclusions: Pts with mCRC rely on their HCPs when making treatment decisions and wish for more power in the process. Personal finance and insurance coverage play dominant roles in treatment for mCRC. PAGs are an important resource for treatment information that are underutilized. Treatment experience of pts with mCRC in an online US survey. n (%) All pts N=344 Black pts n=87 c Hispanic pts n=75 c White pts n=158 Received treatment 256 (74) 52 (60) 60 (80) 129 (82) Chemotherapy a 169 (66) 23 (44) 33 (55) 104 (81) Surgery a 147 (57) 23 (44) 32 (53) 86 (67) Radiotherapy a 101 (39) 25 (48) 15 (25) 52 (40) Immunotherapy a 72 (28) 16 (31) 20 (33) 30 (23) Targeted therapy a 61 (24) 12 (23) 14 (23) 30 (23) Other a 13 (5) 0 0 12 (9) Stopped treatment due to overall burden a ,b 92 (36) 28 (54) 33 (55) 27 (21) Had to decide between treatment or basic needs 198 (58) 60 (69) 52 (69) 69 (44) a Among pts who received treatment. b Financial impact, quality of life, etc. c Base size <100 pts; interpret results directionally.

A novel multi-stage precision reliability assessment method for mechanical system by Bayesian fusion

Precision reliability is crucial for evaluating mechanical system performance. However, limited data makes reliability assessment challenging due to difficult data collection and small sample sizes. Currently, little research has focused on using initial theoretical models as prior information for reliability assessment. This paper proposes a multi-stage precision reliability assessment method for a mechanical system by Bayesian fusion, which can effectively integrate design phase models with usage phase data under limited data conditions to carry out reliability assessment. First, the mechanical system is divided into meta-action units for precision modeling during the design phase. Then, an initial theoretical precision model is developed by incorporating operational error sources. Next, initial theoretical precision model is used to fit the Wiener process-driven model as Bayesian prior information, and reliability assessment is evaluated under different distribution assumptions for both the prior information and experimental data. This approach combines the prior advantages of the theoretical model with the data processing ability of the data-driven model under no prior data and small sample sizes, improving assessment precision and interpretability. Finally, a case study on a machine tool rotary table system validates the effectiveness of this method.

An examination of noun and verb naming differences in aphasia: effects of lesion site, aphasia type and the use of static or dynamic stimuli

ABSTRACT Background Anomia has been extensively researched within the aphasia literature and a dissociation in naming nouns and verbs has been used in diagnostic classifications and related to lesion location. However, there is evidence that action naming is more difficult for many clinical populations as well as for healthy speakers. Confrontation naming tests have often been used to evaluate anomia, but static depiction has been considered a potential source of error in evaluations of verb naming, since actions are dynamic. Aims The first aim of this study was to examine the ability to name objects and actions in a stroke population and non-brain damaged controls and to explore naming ability in relation to lesion location and aphasia type (fluent or non-fluent). A second aim was to determine if action naming is facilitated by using dynamic rather than static stimuli. Methods & Procedures A cross-sectional study was carried out, where 19 participants with aphasia after stroke and 19 matched controls were included. Type of aphasia was based on connected speech samples. Naming performance was compared on two Swedish naming tests consisting of line drawings of high frequency nouns and verbs respectively, and a subset of action pictures was compared to a test using video depictions of actions as verb stimuli. Outcomes & Results There was a significant difference between nouns and verbs in 11 of 19 participants with aphasia. Only one participant, with a temporo-occipital lesion, had a substantial noun-verb difference (≥30%). Individual results showed some agreement with the fluent-nonfluent classification. However, at group level, there was no significant difference between scores on action and object naming for participants with aphasia. While only the control group achieved significantly higher scores on object than action naming, response latencies were longer for action than object naming for both groups. There was no difference in action naming performance that could be related to the use of dynamic or static stimuli. Conclusions The results suggest that a dissociation in naming nouns and verbs is common in aphasia. This finding underscores the importance of testing action as well as object naming. Even though there was some agreement with aphasia type, the relationship between noun-verb dissociation, lesion location and aphasia type is not straight forward. The study adds to previous findings suggesting that action naming is more difficult than object naming. The question whether action naming is facilitated by using dynamic stimuli needs to be further investigated.

Study of the thermolysis process of copper (II) sulfate pentahydrate by thermovolumometric method

When studying mixtures of minerals, composites of complex composition, and selecting powder catalysts, problems often arise for which the small masses of samples used in thermogravimetry do not provide sample representativeness. This requires the use of other methods of analysis that allow the use of samples ten times larger in mass. The paper presents the results of a study of the thermolysis process of copper (II) sulfate pentahydrate using a thermovolumometric method. During the tests, a sealed container with the analyzed substance and a thermoelectric converter was placed in a tubular furnace. The gas released during thermolysis entered the bubbling tank through the capillary. SoundForge13 and TableCurve 2D programs were used to process experimental data. The sources of error in the thermovolumometric analysis technique are analyzed. Dependencies that can be used to improve its accuracy are given. It was revealed that the value of the repeatability index obtained as a result of assessing the repeatability of the method is 3 °C; in the range of densities of the evolved gases 1. 25 – 1. 43 kg/m3, the resolution of the method in terms of the mass of the substance is 12 – 13 μg. The results obtained can be used to determine the temperatures of phase transitions when studying processes occurring during heating of mineral compositions, as well as the temperatures of decomposition reactions of substances. The accuracy of measurements can be increased by careful sample preparation, reducing the heating rate of the sample and introducing corrections to the measurement result based on the obtained dependencies.

Model and mesh selection from a mCRE functional in the context of parameter identification with full-field measurements

Abstract In this paper, we propose a general deterministic framework to question the relevance, assess the quality, and ultimately choose the features (in terms of model class and discretization mesh) of the employed computational mechanics model when performing parameter identification. The goal is to exploit both modeling and data at best, with optimized model accuracy and computational cost governed by the richness of available experimental information. Using the modified Constitutive Relation Error concept based on reliability of information and the construction of optimal admissible fields, we define rigorous quantitative error indicators that point out individual sources of error contained in the identified computational model with regards to (noisy) observations. An associated adaptive strategy is then proposed to automatically select, among a hierarchical list with increasing complexity, some parameterized mathematical model and finite element mesh which are consistent with the content of experimental data. In addition, the approach is computationally enhanced by the complementary use of model reduction techniques and specific nonlinear solvers. We focus here on experimental information given by full-field kinematic measurements, e.g. obtained by means of digital image correlation techniques, even though the proposed strategy would also apply to sparser data. The performance of the approach is analyzed and validated on several numerical experiments dealing with anisotropic linear elasticity or nonlinear elastoplastic models, and using synthetic or real observations.

Incorporating Power-Law Model and ERA-5 Data for InSAR Tropospheric Delay Correction Analysis

InSAR technology effectively monitors urban subsidence and evaluates the stability of infrastructure across extensive regions. Atmospheric tropospheric delay constitutes a significant source of error that adversely impacts the accuracy of InSAR deformation measurements. The meteorological conditions in the highland basin region are complex, and there is a notable deficiency of sufficient sounding balloon observations. This study replaces the sounding balloon data in the power-law model with ERA-5 data (PLE5) to correct the InSAR atmosphere phase delay. This method was tested in Dali utilizing Sentinel-1 data. By comparing its performance against the GACOS model, traditional linear model, and ERA-5 correction, the PLE5 model exhibited the lowest phase standard deviation. This method provides an alternative approach for applying the power-law model in regions with limited sounding balloon data, enhancing the accuracy of InSAR tropospheric delay correction.

Improving MRI turbulence quantification by addressing the measurement errors caused by the derivatives of the turbulent velocity field - Sequence development and in-vitro validation.

To improve the current method for MRI turbulence quantification which is the intravoxel phase dispersion (IVPD) method. Turbulence is commonly characterized by the Reynolds stress tensor (RST) which describes the velocity covariance matrix. A major source for systematic errors in MRI is the sequence's sensitivity to the variance of the derivatives of velocity, such as the acceleration variance, which can lead to a substantial measurement bias. We developed a Cartesian phase contrast sequence with fast velocity encoding and two separately measured partial echoes with opposite readout directions. This design aims to reduce the high-order gradient moments that are responsible for the described measurement error. Velocity encoding directions follow the ICOSA6 scheme to capture the full RST. Turbulence data is reconstructed using the intra-voxel phase dispersion (IVPD) technique. We validated this sequence in vitro using a periodic hill flow benchmark with highly anisotropic turbulence. MRI data underwent extensive averaging, with multiple velocity encoding values employed to reduce noise and isolate systematic effects. The RST data obtained from the new sequence agree well with the ground truth. Compared to a state-of-the-art sequence, the maximum errors were reduced by factor five. Simple adjustments to current MRI protocols can greatly enhance turbulence measurement accuracy through the reduction of high-order gradient moments. The proposed measures include applying fast velocity encoding, high readout bandwidth, and a highly asymmetric readout. Ringing artifacts due to the asymmetric readout can be removed via a second, inverted readout.

Software solution for integration of frozen section quality assurance into daily practice.

Diagnoses rendered using the frozen section (FS) technique during surgical procedures are used to guide intraoperative decisions. Therefore, diagnostic FS errors have the potential to affect patient safety and quality of care. Diagnostic FS errors arise due to both technical and interpretative factors and present a challenge to surgical pathology laboratories to recognize, document, and manage in a timely fashion. Thus, there is a need to monitor discrepancies between FS and permanent diagnoses and effectively communicate with the clinical teams when an error is discovered to ensure an opportunity for timely interventions, if clinically indicated. Our FS practice is complex, with many contributing variables, such as a partially generalized FS pathology practice model among pathology faculty and/or surgeons with specific subspecialty expertise and different physical locations of FS facilities. We implemented a comprehensive frozen section quality assurance (FSQA) program using custom software solutions aimed at improving patient safety by monitoring recognition, increasing documentation, and facilitating communication in cases where there is a discordance between intraoperative and permanent diagnoses. Our FSQA program allows for categorizing frozen section discrepancies according to the source of error, such as interpretive vs technical errors, to understand how errors arise and todevelop appropriate mitigation strategies for reducing errors. Overall, our intervention to improve FSQA has engaged pathology faculty in a uniform and systematic manner, and our data show that our new FSQA program led to a markedly shortened time interval of FSQA, allowing for timely management and resolution of errors.

A method for calibrating robotic kinematic parameters based on a multi-error source model and an optimized measurement pose set

Purpose The purpose of this study is to improve the accuracy of industrial robot kinematic parameter identification and position accuracy by solving the problem of insufficient consideration of error sources in the kinematic parameter identification model and optimizing the selection of measurement pose set. Design/methodology/approach In this study, a kinematic calibration method for industrial robots considering multiple error sources is proposed. Based on the Modified Denavit Hartenberg (MD-H) model, a robot kinematics identification model including joint reduction ratio error, target ball installation error and coordinate system transformation error is established. Taking the optimal observability index O1 and the minimum flexible deformation as the optimization objectives, a measurement pose set optimization method based on Non-dominated Sorting Genetic Algorithm II (NSGA-II) is proposed to obtain a measurement pose set with higher identification accuracy. Findings Through experiments conducted with the Nantong Zhenkang ZK1400-6 robot as the test subject, the kinematic parameters identified by the optimized measurement pose set are more accurate than the randomly selected measurement pose set, and the positioning accuracy of the robot is improved from 2.11 to 0.31 mm, an increase of 85.3%. Originality/value This study introduces a position error model that comprehensively accounts for the error sources causing positioning inaccuracies. Building on this foundation, a novel flexible deformation index is proposed to quantify the flexible deformation in the measurement pose set, thereby reducing the impact of such deformation on the position error in the model. To the best of the authors’ knowledge, for the first time, this study presents an optimization method for the measurement pose set based on NSGA-II, using the flexible deformation index and observability index as objectives for multi-objective optimization, simultaneously optimizing the pose error and Jacobian matrix in the error model.

High-Accuracy Bandgap Reference of <20 ppm/∘C: A Review

This review discusses the principle of typical bandgap reference circuits and analyzes their sources of errors. In order to provide readers with a clear perspective, we categorize the error sources into four types: (a) amplifier offset; (b) high-order nonlinearity of VBE; (c) current mirror mismatch; and (d) other error sources. For these error sources, the most commonly used methods to reduce or minimize them to achieve high accuracy are summarized. Furthermore, this review explores sub-1V bandgap reference design techniques, addressing the increasing demand for low-power and low-voltage applications. Finally, we provide some suggestions for a future high-accuracy reference design.

Finding and minimizing systematic errors in dual-comb spectroscopy

Abstract With sufficiently high signal-to-noise, several systematic errors become prominent in dual-comb interferometry measurements. This paper reviews several error sources including electrical, photo-detection, amplification and acquisition chain non-linearity. Sources of optical non-linearity such as self-phase modulation, cross-phase modulation and Raman soliton shifting are also covered, as are spectral fringing due to parasitic reflections and back-scattering. The non- linear response of the target sample itself can also be a source of errors. Methods to identify and minimize errors in experimental data are discussed. Good practices, instrument design strategies and tools, such as the dynamic range diagram, are suggested.

An improved carrier-phase-based method for precise time synchronization using the observations from the China Space Station-ground synchronization system

The development of precise time synchronization technology is key to the effective application of time–frequency standards. It will significantly promote the application of precise time–frequency standards in the areas such as Positioning, Navigation, and Timing, lunar navigation, and cutting-edge fundamental physics research. This study presents an improved carrier-phase-based method for time synchronization, which was demonstrated through both laboratory and satellite-ground experiments via the China Space Station (CSS)-ground synchronization system. Initial laboratory experiments confirmed the system’s stability, achieving picosecond-level accuracy, highlighting the robustness of the method in controlled environments. Then, preliminary satellite-to-ground synchronization experiments were conducted using the CSS and ground stations, validating the effectiveness of the carrier-phase-based method. The time synchronization accuracy reached the picosecond-level, significantly surpassing traditional pseudocode techniques, which typically achieve sub-nanosecond level accuracy. Additionally, the Allan Deviation results indicated an improvement in stability by about an order of magnitude compared to traditional pseudocode-based methods. This demonstrates that the carrier-phase-based method can effectively mitigate common sources of system errors and enhance time synchronization capabilities. Therefore, this method can provide an effective technical reference for future applications requiring higher precision in time synchronization.

Identification and correction of phase delay errors for hemispherical resonator gyroscopes

The phase-delay error of the circuit system is the primary source of the output error observed in the hemispherical resonator gyroscope (HRG). Additionally, the temperature-dependent nature of the phase-delay error results in a deterioration of the initial calibration parameters, which, in turn, significantly impairs the performance of the gyroscope in its intended application. This paper proposes a self-calibration method to effectively suppress the impact of phase-delay error on the application performance of gyroscopes. Firstly, based on the analysis of the influence of phase-delay error on the performance of the whole-angle mode HRG, a sinusoidal interference signal with a small amplitude is introduced into the quadrature control loop of the gyroscope. Then, the angular rate signal is demodulated and calculated to obtain the phase-delay error of the system, which is employed as the compensation value of the reference phase of the PLL to offset the phase-delay error of the circuit system in real-time. The experimental results demonstrate that after the phase-delay error is self-calibrated, the zero-bias output error of the gyroscope is reduced by 5 times, the bias instability is improved by 37.7%, and the self-calibration method of the phase-delay error presented is more strongly robust to temperature changes.

Influence of ground control point reliability and distribution on UAV photogrammetric 3D mapping accuracy

ABSTRACT This study investigates the impacts of Ground Control Points (GCP) reliability, quantity, and distribution on the accuracy of Unmanned Aerial Vehicle (UAV) photogrammetric 3D mapping. Previous studies have predominantly focused on overall accuracy metrics, often overlooking local variations in error distribution and failing to conduct thorough analysis of error sources, potentially resulting in inefficiencies and reduced photogrammetric 3D mapping accuracy due to sub-optimal GCP deployment and processing strategies. By employing a structured framework, this research analyzes GCP roles based on variations in their reliability. Aerial images of undulated terrains were analyzed and fifteen distinct GCP configurations were designed which incorporated various distributions and quantities. Random noise was added to simulate GCP reliability unpredictability, subsequently analyzed through a multifaceted approach. The results indicate that GCP reliability influences the upper limit of photogrammetric 3D mapping accuracy and significantly affects the influence of GCP quantity and distribution. It was also found that: when GCP reliability is high (RMSE within 0.1 m; density more than 10 GCP/ k m 2 ), GCP number should prioritize over distribution, ie. accuracy improving as the number of GCPs increases; when GCP reliability is moderated (RMSE within 5 m; density around 5–10 GCP/ k m 2 ), each of the uniform and distributed-edge distributions leads in different conditions; when GCP reliability is low (RMSE beyond 5 m; density less than 5 GCP/ k m 2 ) it is favorable to use a distributed-edge and center distribution. Errors typically originate in edge areas and regions with significant topographic variations and propagating as GCP reliability decreases. Therefore, additional GCPs should be placed in error-prone regions to improve the accuracy.

Electrochemical Impedance based Characterization of Membrane Separators

Abstract Separators used in classical alkaline electrolyzers have to prevent gas crossover while keeping the potential drop due to the separator to a minimum. Impedance measurements are an important way of characterizing resistivity of membrane separators. A variety of hardware has been used in the literature for such characterization. The objective of this study is to compare the relative merits and demerits of different kinds of cell hardware for such measurements. We propose the use of coin cells in membrane characterization. Here, we have compared a conventional conductivity cell with a coin cell and a T-cell, by electrochemical impedance spectroscopy studies on commercial Zirfon® membranes in 0.1M NaOH electrolyte. In the latter two cases, several configurations of membrane-electrode assembly have been studied in order to establish the reproducibility and reliability of measurements. The coin cell and T–cell hardware are seen to improve the reproducibility and reliability significantly over the conductivity cell for electrochemical characterization of membranes. Pros and cons along with possible sources of error in measurement have been analyzed in each case. The impedance data for Zirfon® in both coin and T-cell setup was observed to be reproducible and internally consistent.

An Effective Robust Total Least-Squares Solution Based on “Total Residuals” for Seafloor Geodetic Control Point Positioning

Global Navigation Satellite System/Acoustic (GNSS/A) underwater positioning technology is attracting more and more attention as an important technology for building the marine Positioning, Navigation, and Timing (PNT) system. The random error of the tracking point coordinate is also an important error source that affects the accuracy of GNSS/A underwater positioning. When considering its effect on the mathematical model of GNSS/A underwater positioning, the Total Least-Squares (TLS) estimator can be used to obtain the optimal position estimate of the seafloor transponder, with weak consistency and asymptotic unbiasedness. However, the tracking point coordinates and acoustic ranging observations are inevitably contaminated by outliers because of human mistakes, failure of malfunctioning instruments, and unfavorable environmental conditions. A robust alternative needs to be introduced to suppress the adverse effect of outliers. The conventional Robust TLS (RTLS) strategy is to adopt the selection weight iteration method based on each single prediction residual. Please note that the validity of robust estimation depends on a good agreement between residuals and true errors. Unlike the Least-Squares (LS) estimation, the TLS estimation is unsuitable for residual prediction. In this contribution, we propose an effective RTLS_Eqn estimator based on “total residuals” or “equation residuals” for GNSS/A underwater positioning. This proposed robust alternative holds its robustness in both observation and structure spaces. To evaluate the statistical performance of the proposed RTLS estimator for GNSS/A underwater positioning, Monte Carlo simulation experiments are performed with different depth and error configurations under the emulational marine environment. Several statistical indicators and the average iteration time are calculated for data analysis. The experimental results show that the Root Mean Square Error (RMSE) values of the RTLS_Eqn estimator are averagely improved by 12.22% and 10.27%, compared to the existing RTLS estimation method in a shallow sea of 150 m and a deep sea of 3000 m for abnormal error situations, respectively. The proposed RTLS estimator is superior to the existing RTLS estimation method for GNSS/A underwater positioning.

Research on Inertial Isolation Rotation Modulation of Dual-Axis Inertial Navigation Based on Multi-Error Coupling Characteristics

Currently, research on the rotational modulation of dual-axis inertial navigation for isolated carrier motion does not provide sufficient solutions for the compensation of the gyroscope scale factor error caused by the Earth’s rotation. Moreover, it is primarily applied to ships with low maneuverability and has not yet been implemented in the field of pure inertial guidance weapons. A dual-axis inertial isolation rotation modulation method is proposed to address this issue, taking into account the application characteristics of long-endurance guided weapons. An analysis of the system error characteristics under the coupling of multiple error sources acting on IMU was conducted, and it was found that the angular velocity of the inertial isolation carrier can significantly reduce the output error of the IMU. A dual-axis inertial isolation shaft system installation error compensation algorithm was designed, and an improvement was made based on the traditional sixteen-sequence rotation scheme to compensate for the projection components of the Earth’s rotation and carrier motion on the inner and outer frame rotation axes, achieving the inertial isolation rotation modulation function of dual-axis inertial navigation. Based on the attitude changes in long-range guided weapons, Monte Carlo simulation verification was conducted, and the results showed that this scheme can improve inertial navigation accuracy by 10% to 20%.

A review of error analysis and calibration techniques for spherical coordinate 3D laser scanners: Focus on non-instrumental and non-geometric factors

Both Terrestrial Laser Scanners (TLSs) and Metrological Laser Radars (MLRs) are typical Spherical Coordinate Laser Scanners (SCLSs), which are used for various fields requiring surface 3D scanning. TLSs are popular in historical preservation and archiving, reverse engineering, surveying geographic modeling, and digital cities, etc. MLRs, on the other hand, are primarily applied in large-scale precision measurements in industrial manufacturing due to their high accuracy in scanned 3D points. The 3D point precision of both TLSs and MLRs is affected significantly by geometric errors inside instruments. While the geometric errors of SCLSs have been reviewed in some studies, a systematic review of external non-instrumental errors and internal non-geometric errors for TLSs and MLRs is still lacking. These error sources also affect the measurement accuracy of SCLSs. This paper aims to review the quantitative and qualitative analysis of external non-instrumental errors and internal non-geometric errors in TLSs and MLRs. The external non-instrumental errors are further classified into surface properties, scanning geometry, and working environment in this review. For internal non-geometric errors, current research primarily focuses on laser signal processing but lacks studies on error mechanisms and their impact on accuracy. Most existing studies address Time-of-Flight (ToF)-based TLSs, with limited attention given to MLRs. While external factors such as scan depth and surface reflectance are well-studied, environmental factors like temperature remain underexplored. Additionally, there is insufficient research on error compensation models for external factors. Future research on MLRs may focus on several aspects. These include analyzing external non-instrument error factors qualitatively and quantitatively, developing error compensation models, studying the impact of the working environment, and evaluating uncertainty using large-scale standard objects. This review may be beneficial for understanding the research development about the non-instrumental and non-geometric errors of SCLSs.

How to: correctly read scientific articles : Research design and methodology

Criteria for assessment of the significance of scientific articles are presented. The focus is on research design and methodology, illustrated by the classical study on prehospital volume treatment of severely injured individuals with penetrating torso injuries by Bickell etal. (1994). Awell-thought out research design is crucial for the success of ascientific study and is documented in astudy protocol beforehand. Ahypothesis is aprovisional explanation or prediction and must be testable, falsifiable, precise, and relevant. There are various types of randomization methods, with the randomized controlled trial being the gold standard for clinical interventional studies. When reading ascientific article it is important to verify whether the research design and setting align with the research question and whether potential sources of error have been considered and controlled. Critical scrutiny should also be applied to references, the funding and expertise of the researchers.

Child welfare worker perspectives on documentation and case recording practices in Canada: A mixed-methods study protocol.

In health care and child welfare, clinical records and case notes serve multiple functions. When records are aggregated and processed to create administrative data, they can be analyzed and used to inform policy development and decision-making. To be useful, such data should be complete, accurate, and recorded in a standardized way. However, sources of bias and error can impact the quality of administrative data. During the development of national child welfare data in Canada, child welfare sector partners expressed concerns about the accuracy and completeness of data about children and families. This protocol describes a study that seeks to answer two questions: 1) What individual and institutional factors influence how client data is recorded by child welfare workers in Canada? 2) What data quality issues are created through documentation and case recording practices that may impact the use of clinical case management system data for public health statistics? In this protocol, we describe an exploratory mixed methods study that involves an online survey, interviews with a purposive sample of child welfare workers, and a document review of case recording guidelines. To be eligible for the study, participants must have worked at a child welfare agency or department with clinical documentation responsibilities as a part of their job. We will use descriptive statistics to analyze the survey data and thematic analysis to analyze the qualitative data. This study will help uncover strengths, limitations, and possible sources of bias created through case recording and documentation practices in child welfare. Study results will be shared through presentations to interest holders and will inform the further development of national child welfare data in Canada.