Diagnosing intramammary infections: Evaluating expert opinions on the definition of intramammary infection using conjoint analysis
Bibliographic record
Abstract
The primary purpose of this study was to develop a set of criteria to serve as a pseudo-gold standard for what constitutes an intramammary infection using data from 3 consecutive quarter milk samples taken 1 wk apart. Data from lactating cows in 90 dairy herds in 4 Canadian provinces were used to generate the data sets (profiles) used in the conjoint analysis to elicit expert opinions on the topic. The experts were selected from the participants (n=23) in the 2007 Mastitis Research Workers' Conference in Minneapolis and from a series of mastitis laboratory courses for bovine practitioners (n=25) in the Netherlands. Three-week udder quarter profiles with specific combinations of somatic cell count, bacterial species isolated, and plate colony count were selected and included in the conjoint analysis based on the desire to achieve even distributions in the categories of 6 constructed variables. The participants were presented with 3 sets of cards with 20 cards in each set. On each card, they were asked to assign a probability of infection on the middle day (test day) in the 3-wk profile. Depending on the set of cards, they were asked only to be concerned with the probability of infection with coagulase-negative staphylococci, Escherichia coli, or Staphylococcus aureus. These 3 organisms were chosen to represent a minor pathogen, a major environmental pathogen, and a major contagious pathogen, respectively. The assigned probabilities for each organism were cross-tabulated according to the number of times the organism of interest was isolated in the 3-wk period, how many colonies of the organism of interest were isolated on the test day, and the somatic cell count (<or= or >200,000 cells/mL). There was considerable variation in the assigned probabilities within each of the combinations of factors. The median, minimum, and maximum values of the assigned probabilities for each combination were computed. The combinations with a median probability >50% were considered intramammary infection-positive and included as a criterion in the consensus standard. This yielded 4 possible criteria, which were condensed to the following 2 by consensus at the 2008 Mastitis Research Workers' Conference in Toronto: 1) the organism of interest was isolated on the test day with at least 10 colonies (1,000 cfu/mL), and 2) the organism of interest was isolated at least twice in the 3-wk period.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.004 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".