g.ekstrom, post #26: Understood. Thank you for being specific about the limits of it. Go to post
Acknowledging rather than arguing. The reasoning holds as far as I can follow it.
Data & Tools · Calculators · continued
Validating a calculator against hand arithmetic — what changed since posts 61–90
This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1 · go to the accepted answer.
Coming back to post #60, because the follow-up matters more than the original answer.
Two people in this thread mean different things by Validating a calculator against hand and are disagreeing about the definition while believing they are disagreeing about the facts. Worth pausing to define it.
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g.pemberton_uk, post #35: Reporting bugs: if you notice a calculator giving wrong results, report it in this subcategory. Bugs are fixed when identified. One case, stated as one case. Go to post
Confirming post #62 from a second method, which matters more than confirming it from a second person.
Where a calculator and your own arithmetic disagree, the productive move is to find which step differs rather than to decide which is right.
That holds for the case as described. Change the assumptions and it may not.
If someone has run Validating a calculator against hand properly I would rather read that than my own reconstruction of it. Posting mine only because the thread has gone quiet.
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A saved calculation is worth more than a remembered one. Write down the inputs alongside the result, because the result alone is unverifiable a month later.
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m.adebayo, post #44: Post #42 describes the usual case. This is about the unusual one. The calculators maintained on this site are open-source and verifiable. They are intended to check arithmetic, not to replace medical judgement. Using them is optional and they are provided for convenience. It is worth stating the boring hypothesis before the interesting… Go to post
What I would want before treating Validating a calculator against hand as settled: the method, the sample, and whether anyone tried to find the opposite result. Two of the three are usually missing.
PSkarbek, post #60: Confirming post #57 from a second method, which matters more than confirming it from a second person. A calculator that shows its working is worth ten that give an answer. The whole value is being able to see which step you disagree with. That holds under the stated conditions and I have stated them. Go to post
That is consistent with mine, for whatever one more account is worth.
dexa_twice_yearly, post #33: Practical note on Validating a calculator against hand: write down what you expect before you look. The number of times I have found what I went looking for is higher than chance would allow. Go to post
Everything in post #67 holds. The case it does not cover is the one I have.
I would rather this thread reach "we do not know" about Validating a calculator against hand than reach a confident answer that nobody can support when asked.
Narrowing post #71, because the general version has more than one answer.
Tools that run entirely in the browser send nothing anywhere, which matters more to some people here than others and is worth stating either way.
I would not lead a decision with this, but I would not ignore it either.
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Reconstitution calculator: enter vial mass, final volume target, and the calculator tells you concentration and syringe mark for a given dose. Useful for double-checking arithmetic when you are doing it by hand.
Adding it because I spent an afternoon working it out and nobody should have to twice.
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Post #75 answers the question as asked. The question underneath it is different.
I think the Validating a calculator against hand question is answerable and has not been answered, which is a more optimistic position than most of this thread.
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footnote_entry, post #45: Unit-conversion tools are only as good as the assumption they make about the syringe. Ask what barrel and what graduation interval it assumed before trusting the units figure. Go to post
Dose equivalence calculator: compounds have different potencies. The calculator is provided with a caveat: "equivalence" is not precise and individual response varies. It is a rough starting point, not a dose prescription.
Titration planning: a calculator that shows you the escalation schedule for different starting and ending doses can help you visualize your path. Actual path might be slower or adjusted for tolerability.
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Storage lookup: which conditions (temperature, time) are you considering storing in, and how much stability loss is expected? The calculator gives a rough estimate based on typical stability data. Not a substitute for your compound's specific stability data.
Marking that as an opinion rather than a finding.
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Leiterman, post #25: On Validating a calculator against hand I would separate what is worth knowing from what is worth acting on. The first list is long and the second is short, and conflating them is how threads get heated. Go to post
Maintaining a calculator means checking the arithmetic against hand-worked cases at each review, not checking that it still loads.
m.adebayo, post #44: Post #42 describes the usual case. This is about the unusual one. The calculators maintained on this site are open-source and verifiable. They are intended to check arithmetic, not to replace medical judgement. Using them is optional and they are provided for convenience. It is worth stating the boring hypothesis before the interesting… Go to post
Nothing a calculator produces is medical advice, and a correct calculation on inappropriate inputs is still an inappropriate answer.
Building on post #80 rather than restating it.
Validating a calculator against hand looks different depending on whether you are reading the primary literature or the summaries of it, and the difference is not in our favour.
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Post #82 put the caveat in the right place and I want to underline it.
Small methodological point on Validating a calculator against hand: repeating a measurement is cheap and resolves most of what is being argued about here at no cost to anyone.
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Collapsed as off-topic by two members at trust level 3 or above
Narrowing post #84, because the general version has more than one answer.
Why calculators are not medical advice: they do arithmetic. Medical decisions are not arithmetic. A calculator that says a certain dose is "compatible with" a certain body mass is not a prescription.
The number is defensible. The precision I gave it is not.
crossover_review, post #37: Significant figures in the output should not exceed what the inputs support. A concentration calculated from a nominal vial mass is not known to four decimal places. Go to post
I would keep Validating a calculator against hand and the decision it usually gets used for separate in this thread. They are related and they are not the same question, and merging them is why the last one went badly.
That is a fair summary of where the discussion has got to.
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g.pemberton_uk, post #9: Where I have landed on Validating a calculator against hand, having got it wrong once in public: the direction is clear, the magnitude is not, and anyone quoting a precise magnitude has borrowed it from somewhere that did not measure it. Go to post
Precision and significant figures: the calculators do not round to match your input precision. If you input values to one decimal place, the output might have more. Use significant figures appropriate to your input precision.
It is worth checking rather than assuming, which costs nothing.
On post #86 — agreed on the reasoning, with one qualification.
Careful with the language on Validating a calculator against hand. "Not detected" and "not present" are different findings and the first is a statement about the method.
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