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PubMed1995

Accuracy of a voice-to-text personal dictation system in the generation of radiology reports.

OBJECTIVE: Systems that convert spoken words directly into text have recently become available. The purpose of this study was to test the accuracy, on a word-for-word basis, of one such system for generating radiology reports. MATERIALS AND METHODS: The IBM Personal Dictation System (IPDS), with the optional add-on radiology vocabulary, was assessed (the system is now known as VoiceType Dictation). The system requires one to use discrete speech (i.e., with a momentary pause between words). Two hundred current radiology reports, including 100 consecutive chest radiographs, 50 consecutive thoracic CT scans, and 50 random sonography and angiography reports, were read to the system. Before testing, the IPDS had been used in the dictation of material related to chest radiology. All errors were noted on a word-for-word basis and categorized as follows: incorrect, partially incorrect (no effect on meaning), not in dictionary (word was then added), homophone, or formatting. Medical words (those thought to be relevant to the meaning of the report) were considered separately. Specific assessments of numbers and dates were made. Words added to the dictionary were reread after the 200 reports had been assessed. RESULTS: When all mistakes were considered, the accuracy was 0.99 for chest radiology and 0.96 for material not concerning chest radiology. When only relevant mistakes on medical words were considered, the accuracies were 0.98 and 0.96, respectively. Accuracy for numbers was 0.95 and for dates 0.97. Redictation of the 22 words previously not in the dictionary was 100% accurate. CONCLUSION: The IPDS is an accurate system for direct voice-to-text dictation of radiology reports that improves with continued use. The most important future enhancement of such systems will be to allow the more natural continuous or conversational speech style.

Humans↗
PubMed1996

Diagnostic accuracy and safety of CT-guided percutaneous needle aspiration biopsy of the lung: comparison of small and large pulmonary nodules.

OBJECTIVE: The purpose of this study was to compare the diagnostic accuracy and safety of CT-guided percutaneous needle aspiration biopsy of pulmonary nodules less than or equal to 1.5 cm in diameter with those of nodules greater than 1.5 cm in diameter. MATERIALS AND METHODS: We retrospectively reviewed a consecutive series of 97 patients who underwent CT-guided percutaneous needle aspiration biopsy of a lung nodule and then surgical resection (n = 95) or autopsy (n = 2). By examining CT images, we classified 27 nodules as small ( < or = 1.5 cm) and 70 nodules as large ( > 1.5 cm). Diagnostic accuracy was calculated by comparing cytologic diagnoses based on biopsy with final diagnoses based on histologic findings from surgery or autopsy. Each case was reviewed for possible complications, including pneumothorax and chest tube placement. RESULTS: The diagnostic accuracy of CT-guided percutaneous needle aspiration biopsy of large nodules was 96%. The diagnostic accuracy for small nodules was 74%, a statistically significant difference (p < .05). The prevalences of pneumothorax in our population were nearly identical for small and large nodules (22 and 21%, respectively). The prevalence of chest tube placement in our population was approximately 2%. The prevalences of chest tube placement were 0% for small nodules and 3% for large nodules. CONCLUSION: CT-guided percutaneous needle aspiration biopsy is significantly less accurate for small pulmonary nodules than for large pulmonary nodules, but the complication rates for both are low.

Adult↗
PubMed1997

Hepatosplenic fungal disease: diagnostic accuracy and spectrum of appearances on MR imaging.

OBJECTIVE: We describe our 6-year experience in the prospective examination of patients with suspected hepatosplenic fungal disease to show the diagnostic accuracy of MR imaging and the spectrum of appearances on MR images. SUBJECTS AND METHODS: All patients who underwent MR examination for suspected hepatosplenic fungal disease from January 1990 to January 1997 in three university institutions were included in the study. Patients presented with persistent fever or no response to antibacterial antibiotics. Patients were grouped as acute, subacute treated, and chronic treated, according to the duration of their symptoms. Patients with 2 weeks or fewer of possible infection were acute presentation, patients on antifungal therapy longer than 2 weeks but shorter than 3 months were subacute treated presentation, and patients on antifungal therapy for 3 months or longer or who had completed antifungal therapy and had a history of hepatosplenic fungal disease were chronic treated presentation. MR studies were prospectively interpreted for the presence of hepatosplenic fungal lesions. The appearances of fungal lesions in patients in each category were determined. The sensitivity, specificity, positive predictive value, negative predictive value, and accuracy for detecting lesions in patients with acute presentation were also determined. RESULTS: Sixty-nine patients were included in the study. MR imaging revealed signs consistent with hepatosplenic fungal lesions in 22 (32%) of 69 patients and no demonstration of hepatosplenic lesions in 47 (68%) of 69 patients. In the 60 patients with acute presentation, MR imaging in 13 patients revealed hepatosplenic lesions that were interpreted as fungal disease. True-positive lesions were present in 11 of these 13 patients. These lesions measured less than 1 cm in diameter and were best shown as well-defined high-signal-intensity foci on T2-weighted images. The remaining two of the 13 patients had false-positive lesions; one was shown to have tuberculosis, and the other had graft-versus-host disease. For acute presentation, MR sensitivity was 100%, specificity was 96%, positive predictive value was 85%, negative predictive value was 100%, and accuracy was 97%. In the five patients with subacute presentation, lesions were present that measured less than 1 cm in diameter and were best shown as mildly hyperintense on T1-weighted images. A perilesional ring nearly void of signal intensity was seen on unenhanced and gadolinium-enhanced T1-weighted images in all five patients. The four patients with chronic healed lesions all had lesions that were 1-3 cm in diameter with irregular, angular polygonal margins. These lesions, which were best shown on images obtained immediately after gadolinium administration, appeared as regions of diminished enhancement with no perilesional changes. CONCLUSION: MR imaging has high diagnostic accuracy for the diagnosis of acute hepatosplenic fungal disease. Patients with acute, subacute treated, and chronic healed presentations may have lesions that can be distinguished by their MR appearances.

Acute Disease↗
PubMed1999

CT angiography with volume rendering for quantifying vascular stenoses: in vitro validation of accuracy.

OBJECTIVE: The purpose of this study was to evaluate the accuracy of CT angiography with volume rendering for quantifying vascular stenoses in vitro. MATERIALS AND METHODS: Vascular models with three degrees of stenosis (33%, 67%, and 83%) were imaged at three orientations to the axial plane (parallel, perpendicular, or 45 degrees ) using helical CT with 2-mm collimation and two pitches (1 or 2), two reconstruction intervals (1 or 2 mm), and two scan times (.75 or 1 sec). Diameter and percentage of stenosis were measured from volume renderings using full width at half maximum. Images were measured in two planes whenever resolution varied with direction. Statistical analysis was performed using analysis of variance. RESULTS: Mean absolute error of the measured percentage of stenosis was 7% (range, 0-27%). The actual percentage of stenosis and vessel orientation had the most significant effects on accuracy (p < .001). The measured percentage of stenosis was significantly less accurate with phantoms parallel to the axial plane than with other orientations (p < .001). Mean absolute error in the measured percentage of stenosis was 4% when the parallel-to-the-axial-plane orientation was excluded. Overlapping (1-mm) reconstructions were significantly more accurate than 2-mm reconstructions (p < .05) and direction of measurement significantly affected accuracy (p < .05), but these effects were secondary. CONCLUSION: CT angiography with volume rendering can accurately quantify vascular stenoses, but it is less accurate for vessels in the axial plane. With 2-mm collimation, vessel characteristics have greater effects on accuracy than do acquisition parameters.

Analysis of Variance↗
PubMed2003

Standardization of flow velocities with respect to age and sex improves the accuracy of transcranial color Doppler sonography of middle cerebral artery spasm.

OBJECTIVE: The overall accuracy of transcranial Doppler sonography in the diagnosis of middle cerebral artery spasm has not been established. Moreover, the factors of age and sex have not been addressed in most studies. In this article, we present receiver operating characteristic (ROC) curve analysis of the accuracy of transcranial color Doppler sonography in diagnosing middle cerebral artery spasm on the basis of flow velocities standardized for age and sex. SUBJECTS AND METHODS. We prospectively studied 214 consecutive patients (110 male, 104 female; age range, 12-77 years) who were routinely referred for cerebral angiography. Middle cerebral artery spasm was graded as mild (</= 25% of vessel caliber reduction) and moderate to severe (> 25% reduction). Angle-corrected blood velocity measurements were obtained using a 2.5-MHz probe. The velocity values were reexpressed as a percentage of the mean of normal reference values for the relevant age, for subjects younger than 40 years, and for sex. RESULTS: The prevalence of spasm among 335 arteries studied was 8.1% for mild and 12.8% for moderate to severe middle cerebral artery narrowing. For distinguishing all or moderate to severe vasospasm from lesser grades of vasospasm, peak systolic velocity was the best parameter. Areas under ROC curves for all and moderate to severe middle cerebral artery spasms were 0.83 and 0.92, respectively. After standardization, the ROC areas increased significantly (p < 0.05) for all, to 0.86, and only slightly, to 0.93, for moderate to severe spasms. For all grades of middle cerebral artery spasm, the best efficiencies were found at standardized velocity value of 170%. CONCLUSION: The accuracy of transcranial color Doppler sonography is high in the identification of middle cerebral artery spasm. Standardization of velocities with respect to age and sex increases the accuracy of the method in diagnosing mild middle cerebral artery spasms.

Age Factors↗
PubMed2005

Diagnostic accuracy of time-resolved 2D projection MR angiography for symptomatic infrapopliteal arterial occlusive disease.

OBJECTIVE: Our objective was to evaluate the diagnostic accuracy of time-resolved 2D projection MR angiography in detecting calf and pedal artery occlusive disease. MATERIALS AND METHODS: Time-resolved MR angiography of calf and pedal arteries was performed on 59 symptomatic legs of 52 patients using the head coil and bolus injections of 6 mL of gadolinium contrast medium. Selective X-ray digital subtraction angiography was performed within 30 days after MR angiography. Calf and pedal arteries were divided into 10 segments. X-ray digital subtraction angiography and MR angiography images were retrospectively interpreted by three expert observers, who graded segments as having no significant stenosis, significant stenosis (> 50%), or occlusion. The accuracy of MR angiography interpretations was compared with the accuracy of consensus X-ray digital subtraction angiography interpretations as the standard of reference. Arterial segments with discrepant grading on X-ray digital subtraction angiography and MR angiography were reviewed again to determine the reasons for disagreement. RESULTS: Arterial phase MR angiography images free of venous contamination were obtained in every case. The agreement between MR angiography and X-ray digital subtraction angiography in depicting infrapopliteal arterial disease was fair to good (kappa = 0.44-0.92). Overall sensitivity and specificity were 83% and 87%, respectively, for detecting significant stenosis of calf and pedal arteries and 86% and 93%, respectively, for detecting occlusions. Accuracy was higher in the larger vessels-for example, calf (84%) compared with foot (71%). In 21% (22/105) of the segments graded differently on MR angiography than on X-ray digital subtraction angiography, it was believed that MR angiography was more likely to be correct than X-ray digital subtraction angiography because of visualization of late-filling arteries on MR angiography that did not opacify on X-ray digital subtraction angiography. CONCLUSION: Time-resolved 2D projection MR angiography accurately evaluates calf and pedal arteries without degradation from venous contamination.

Adult↗
PubMedDate not supplied

[Accuracy of ultrasonic fetal weight estimation using head and abdominal circumference and femur length].

INTRODUCTION: Former investigations have shown that the accuracy of fetal weight estimation is significantly higher if several ultrasonic fetal parameters are measured, because the total body mass depends on the size of fetal head, abdominal circumference and femur length. The aim of this investigation was to establish the best regression model, that is a number of combinations of fetal parameters providing the most accurate fetal weight estimation in utero in our population. MATERIAL AND METHODS: This prospective study was carried out at the Gynecology and Obstetrics Clinic of the Clinical Center Novi Sad. It included 270 pregnant women with singleton pregnancies within 72 hours of delivery who underwent ultrasound measurements of the biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL). RESULTS: In regard to fetal weight estimation formulas, the deviation was lowest using regression models that simultaneously analyzed four fetal parameters (0. 55%) with SD +/- 7.61%. In these models the estimates of fetal weights were within +/- 5% of actual birth weight in 48.89%, and within +/- 10% of actual birth weight in 81.48%. Good results were also obtained using AC, FL measurements (0.92% +/- 8.20) as well as using AC, HC, FL measurements (-1.45% +/- 7.81). In our sample the combination of AC and FL model gave better results in fetal weight estimation (0.92 +/- 8.20%) than the one using BPD and AC (2.97 +/- 8.83%). Furthermore, the model using parameters AC, HC and FL showed a lower error in accuracy (-1.45 +/- 7.81%) than the model using BPD, AC and FL (2.51 +/- 7.82%). CONCLUSION: This investigation has confirmed that the accuracy of fetal weight estimation increases with the number of measured ultrasonic fetal parameters. In our population the greatest accuracy was obtained using BPD, HC, AC and FL model. In cases when fast estimation of fetal weight is needed, AC, HC, FL model may be appropriate, but if fetal head circumference cannot be measured (amnion rupture and/or fetal head already in the pelvis) the AC, FL model should be used.

Abdomen↗
PubMedDate not supplied

Home monitors of blood glucose: comparison of precision and accuracy.

Home monitors of blood glucose (HMBGs) are gaining acceptance as part of the standard of care for ambulatory self-monitoring and treatment of diabetic patients. Currently there are several HMBGs marketed in the United States, each claiming reliability, accuracy, and "user friendliness," with most of these claims largely unsubstantiated. The objective of our study was to analyze and statistically compare the accuracy and precision of the HMBGs produced by the major competitors in this ever-expanding medical field. Accuracy of each monitor was studied by comparing the glucose value reported by each HMBG with that determined by a reference method (YSI 23A). Precision or reproducibility of results was performed by testing a single, known whole-blood glucose sample 20 times on each monitor. The precision of each device was tested on known low, normal, and elevated samples. Actual and absolute deviations from the reference standard demonstrate that the Accuchek bG and Glucoscan 2000 monitors provide relatively unbiased estimates of blood glucose, whereas the Glucokey, Glucochek II, Glucometer II, and Trendsmeter generally underestimate the true values. The Diascan and Accuchek II monitors, in a separate evaluation, demonstrated acceptable accuracy and precision. We conclude that the Accuchek bG and Glucoscan 2000 statistically are the most accurate and precise HMBGs.

Adult↗
PubMed1999

Accuracy of pen injectors versus insulin syringes in children with type 1 diabetes.

OBJECTIVE: To compare the accuracy and precision of insulin syringes and pen devices used by children with type 1 diabetes and their parents. RESEARCH DESIGN AND METHODS: There were 48 subjects (32 patients, a parent of an additional 16 patients) instructed to measure out morning insulin doses three times from vials and/or cartridges containing saline mixed with small amounts of [14C]glucose (solution used as regular insulin) and [3H]glucose (solution used as NPH insulin) and to dispense the contents into a scintillation vial. Statistical analysis was used to determine the accuracy and precision of both methods of insulin delivery. RESULTS: The absolute error in measuring out doses of regular insulin < 5 U was greater with insulin syringes compared with pen injection devices (9.9 +/- 2.4 vs. 4.9 +/- 1.6%, respectively). Both were comparable for regular insulin doses > 5 U (3.2 +/- 0.6 vs. 2.2 +/- 0.4% for syringes and pens, respectively). The accuracy in drawing up NPH doses was similar for low and high insulin doses (mean percent error of 7.5 +/- 1.5 vs. 5.6 +/- 1.1%). CONCLUSIONS: Pen devices are more accurate than insulin syringes in measuring out insulin at low insulin doses. The accuracy of insulin syringes improves when higher doses of regular insulin are measured out and becomes comparable to pen devices.

Adolescent↗
PubMedDate not supplied

Behavioral skills in self-monitoring of blood glucose: relationship to accuracy.

Sixty-two children and adolescents with IDDM were observed while performing self-monitoring of blood glucose (SMBG) to determine which of the behaviors involved in SMBG were most likely to be performed incorrectly and which errors had the greatest effect on the accuracy of SMBG readings. Behaviors related to cleanliness and timing were performed most poorly; only 60% of the subjects correctly timed the first minute, and 30-33% correctly timed the second interval. The duration of SMBG and frequency of monitoring were not related to proper performance of the behaviors involved in SMBG. Accuracy of SMBG was assessed by comparing subjects' readings to laboratory values obtained immediately afterward. The behavior that had the greatest effect on the accuracy of SMBG readings was that concerning whether the blood was adequately wiped from the Chemstrip bG. This behavior should receive more emphasis in SMBG training programs. The systematic observation procedure used in this study may help to identify errors made by patients while performing SMBG and may serve as the basis for training programs to improve SMBG accuracy.

Adolescent↗
PubMed2003

Assessment of the accuracy of computed tomography for measurement of normal equine pituitary glands.

OBJECTIVE: To describe the anatomic features of the pituitary gland region in horses via computed tomography (CT) and determine the accuracy of CT for estimating normal equine pituitary gland dimensions. ANIMALS: 25 adult horses with no clinical signs of pituitary disease. PROCEDURE: Transverse CT images and gross transverse tissue sections were compared in 2 horses. Contrast-enhanced CT of the pituitary gland region was performed postmortem in 23 horses with 4 slice thickness and interval settings (10-mm contiguous or overlapping slices and 4-mm contiguous or overlapping slices). Gross and CT estimates of pituitary gland dimensions were compared via ANOVA. Accuracy of CT estimates was calculated with gross pituitary gland measurements as the known value. RESULTS: Pituitary glands were located between the temporomandibular joints and had contrast enhancement. Mean gross dimensions were length, 2.11 cm; width, 2.16 cm; height, 0.98 cm; and volume, 2.66 cm3. Gross measurements and CT estimates of pituitary gland length from 10-mm contiguous and overlapping slices did not differ. Gross measurements and CT estimates of pituitary gland width from 4-mm contiguous and overlapping slices did not differ. Estimates of height and volume from all CT techniques differed from gross measurements. Accuracies for CT estimates were length, 88 to 99%; width, 81 to 92%; height, 58 to 71%; and volume, 43 to 55%. CONCLUSIONS AND CLINICAL RELEVANCE: Accuracy of estimates of pituitary gland dimension in horses varied with CT scanning technique; via CT estimates of length and width of glands were more accurate than estimates of height or volume.

Animals↗
PubMed2006

A comparison between novices and experts of the velocity-accuracy trade-off in overarm throwing.

Expert team-handball players do not show the typical trade-off between speed and accuracy in overarm throwing. Van den Tillaar and Ettema (2003a) attributed this result to the uniqueness of the training experience of this group. The purpose of this study was to test their hypothesis by comparing experts with novices on overarm throwing by manipulating the goal of the task using different instructions. No trade-off between speed and accuracy was found for novices (n = 13; M age = 22.7 yr., SD = 2.2) or experts (n = 9; Mage = 24 yr., SD = 2.2): accuracy did not change by instruction. Furthermore, the linear velocities of the ball and endpoints of body segments and their timing were affected by instruction in a similar fashion in both groups. This finding indicates that training experience is not related to speed-accuracy tradeoff in overarm throwing.

Acceleration↗
PubMed1996

Effects of training in monitoring accuracy on processing speed in mental retardation.

Monitoring accuracy during choice RT allows subjects to maintain fast, safe RT bands and avoid overly fast, unsafe RT bands. 5 retarded adults received trial-by-trial feedback on accuracy over a number of sessions to train monitoring of accuracy and to improve RT performance. Training was introduced according to a multiple-baseline-across-subjects (with reversal) design. Training had no significant effect on subsequent RT performance, suggesting that inefficient monitoring of accuracy may be a structural characteristic of mental retardation.

Adult↗
PubMed1993

The contribution of progeny of uncertain paternity to the accuracy of sire evaluation.

Recent advances in statistical methodology now permit the genetic evaluation of animals with uncertain pedigrees. Although widescale practice of these techniques is not likely, implementation will never occur until we characterize the effect of uncertain pedigrees on the accuracy of animal evaluation. This work develops the framework for such a characterization, illustrating the contribution of uncertainly identified records to accuracy of evaluation through a hypothetical example. The effect of including records of uncertain paternity is greatest for sires with few certainly identified progeny. Thus, young sires stand to benefit the most from the inclusion of progeny records with uncertain paternity. In general, as the level of uncertainty in the data is replaced by the inclusion of progeny with certain paternity, the accuracy of evaluation increases. However, situations do arise in which the accuracy unexpectedly declines with the addition of progeny records with certain paternity.

Animals↗
PubMed1980

Automated differential leucocyte counters: an evaluation of the Hemalog D and A comparison with the Hematrak. I. Principles of operation; reproducibility and accuracy on normal blood samples.

The precision and accuracy of the Hemalog D, which uses cytochemical identification of cells in suspension, and of the Hematrak, which uses image recognition of cells on a stained blood film, have been compared counting normal blood samples. The Hemalog D showed superior precision for all cell types, as would be expected since 10,000 cells are counted per sample; however, the precision for monocytes was worse than expected for the number of cells counted. The precision of the Hematrak was equivalent or superior to that of a manual count of the same number of cells but showed the poor precision inevitable when only 100 cells are counted. With respect to accuracy, both automated counters showed statistically significant differences from manual counts and from each other in counting neutrophils, lymphocytes and eosinophils, bu the differences were not sufficiently great to be of practical importance. The Hematrak counted monocytes accurately (though imprecisely) whereas the Hemalog D overestimated monocytes on average by 2.3%, or 40% of the mean monocyte percentage. This was consequent on the counting of esterase positive neutrophils as monocytes, and the difference from the manual count was sufficient to be of some practical importance. The Hemalog D counted basophils both accurately and precisely. The precision of manual and Hematrak basophil counts was poor; the accuracy of the Hematrak basophil count was dependent on the quality of the stain and that of the manual basophil count was dependent on the quality of the stain and the attentiveness of the technologist. For other cell types in blood samples from normal volunteers, the Hematrak was versatile and accuracy was not greatly affected by the use of May-Grünwald-Giemsa rather than Wright's stain, nor by the use of hand spread rather than machine spread films.

Automation↗
PubMed2003

Accuracy of computer assisted percutaneous placement of iliosacral screws: a cadaveric study.

OBJECTIVE: To determine the accuracy of computer-assisted fluoronavigation for percutaneous iliosacral screw placement. MATERIALS AND METHODS: A fluoronavigation system (Stryker Navigation System, Stryker Leibinger, Kalamazoo, MI) was used to guide the placement of four iliosacral screws into the S-1 bodies of each of five cadaveric pelvic specimens with intact soft tissues. Accuracy of screw placement was verified by radiographs, CT scans, and direct dissection. RESULTS: All 20 screws were placed accurately without complications. Nineteen screws were completely contained within the osseous "safe zone." On direct dissection, one screw was noted to have penetrated the S-1 foramina by 3 mm without impingement on the nerve root. This was not detected on radiograph or CT scan. CONCLUSION: The results of this study support the safety and accuracy of computer-assisted fluoronavigation for iliosacral screw placement. The advantages include decreased fluoroscopic time, real-time simultaneous visualization of all three views (inlet, outlet, and lateral), and increased accuracy of placement. Clinical study is warranted.

Bone Screws↗
PubMed2004

The application accuracy of a skull-mounted trajectory guide system for image-guided functional neurosurgery.

OBJECTIVE: Frameless image guided systems have traditionally been perceived as being less accurate than stereotactic frames, limiting their adoption for trajectory-based procedures such as deep brain stimulator placement which require submillimetric accuracy. However, some studies have suggested that high degrees of accuracy are attainable with optical localization systems. We evaluated the application accuracy of a skull-mounted trajectory guide coupled to an optical image-guided surgery system in a laboratory setting. MATERIALS AND METHODS: A plastic skull phantom was fitted with five fiducial markers rigidly attached via self-drilling bone screws. Varying MRI and CT imaging protocols were obtained at 25 different centers. A metal disc marked in 1-mm increments was placed at the expected target point. Following registration and alignment of the trajectory guide, radial and depth localization errors were measured. A total of 560 measurements were obtained and detailed statistical analyses were performed. RESULTS: Mean localization error was 1.25 mm with a 95% confidence interval of 2.7 mm and a 99.9% confidence interval of 4.0 mm. These values were significantly lower than those published for the two most widely used frame systems (p<0.001). CONCLUSIONS: Accuracy of image-guided localization using a rigid trajectory guide can meet or exceed that achievable with a stereotactic frame.

Humans↗
PubMed1994

Measuring efficiency and accuracy of detection of estrus.

The ability of management to detect estrus efficiently and accurately in cows and heifers profoundly influences reproductive performance and profitability of dairy herds. Routine estimates of efficiency and accuracy are important to monitor reproduction in a herd and to evaluate management in problem breeding herds. Detection efficiency is usually expressed as the percentage of possible estruses that were observed over a given time period. Eight methods are presented that approximate efficiency using estrus and insemination dates. Efficiency can be estimated from herd summary information using the equation recommended by the Dairy Reproduction Core Parameter Committee or using equations that calculate the breeding interval. Milk progesterone concentrations measured by on-farm tests can be used to approximate efficiency. Seven of the nine Dairy Record Processing Centers calculate an efficiency estimate. Accuracy of detection of estrus is the percentage of estruses observed that are true estruses. Inaccurate detection of estrus results in breeding of cows not in estrus, thus lowering conception rates. Detection accuracy should be evaluated for herds experiencing low conception rates. Comparison of interestrual intervals, results of uterine and ovarian palpation, and progesterone concentrations of cows perceived to be in estrus can be used to estimate the accuracy of detection of estrus.

Animals↗