In general, NNT is always computed with respect to two treatments A and B, with A typically a drug and B a placebo ( in our example above, A is a 5-year treatment with the hypothetical drug, and B is no treatment ).

If the probabilities pA and pB of this endpoint under treatments A and B, respectively, are known, then the NNT is computed as 1 /( pB-pA ).

The NNT for breast mammography is 285 ; that is, 285 mammograms need to be performed to diagnose one breast cancer.

An NNT of 1 is the most effective and means each patient treated responds, e. g., in comparing antibiotics with placebo in the eradication of Helicobacter pylori.

An NNT of 2 or 3 indicates that a treatment is quite effective ( with one patient in 2 or 3 responding to the treatment ).

Similarly, some poorly designed earlier trials found that peppermint oil has the ability to reduce colicky abdominal pain due to IBS with an NNT ( number needed to treat ) around 3. 1, but the oil is an irritant to the stomach in the quantity required and therefore needs wrapping for delayed release in the intestine.

Compared to placebo ( which also is associated with symptom improvement ), they have a number needed to treat ( NNT ) of eight ( 8 ).

The number needed to treat ( NNT ) is an epidemiological measure used in assessing the effectiveness of a health-care intervention, typically a treatment with medication.

The ideal NNT is 1, where everyone improves with treatment and no one improves with control.

The higher the NNT, the less effective is the treatment.

In general, NNT is computed with respect to two treatments A and B, with A typically the intervention and B the control ( e. g., A might be a 5-year treatment with a drug, while B is no treatment ).

If the probabilities p < sub > A </ sub > and p < sub > B </ sub > of this endpoint under treatments A and B, respectively, are known, then the NNT is computed as 1 /( p < sub > B </ sub > – p < sub > A </ sub >).

NNT is a number between 1 and ∞; effective interventions have a low NNT.

A negative number would not be presented as a NNT, rather, as the intervention is harmful, it is expressed as a number needed to harm ( NNH ).

The NNT is an important measure in pharmacoeconomics.

If a clinical endpoint is devastating enough ( e. g. death, heart attack ), drugs with a high NNT may still be indicated in particular situations.

If the endpoint is minor, health insurers may decline to reimburse drugs with a high NNT.

Even though NNT is an important measure in a clinical trial, it is infrequently included in medical journal articles reporting the results of clinical trials.

There are a number of factors that can affect the NNT.

Here the reciprocal is especially meaningful and is known as the number needed to treat ( NNT ): 1 /( 20 %)

The NASCET found that for every six patients treated, one major stroke would be prevented at two years ( i. e. a number needed to treat ( NNT ) of six ) for symptomatic patients with a 70 – 99 % stenosis, where percent stenosis was defined as:

As another example, an NNT of 4 means if 4 patients are treated, only one would respond.

Symptomatic patients with less severe carotid occlusion ( 50 – 69 %) had a smaller benefit, with a NNT of 22 at five years ( Barclay ).

An NNT of 20 to 40 can still be considered clinically effective.

A meta-analysis of randomized controlled trials suggests alginic acid may be the most effective of non-prescription treatments with a NNT of four.

For example, if a study ran for 5 years and it was found that the NNT was 100 during this 5 year period, in one year the NNT would have to be multiplied by 5 to correctly assume the right NNT for only the one year period ( in the example the one year NNT would be 500 ).

" A strike ... ended on Friday, 6 August, after some 1, 500 miners of the PT NNT labour union, affiliated to the Chemical, Energy, Mine Workers ’ Union of the Indonesia Workers ’ Union, agreed to await an overtime pay judgment from a provincial government.

NNT values are time-specific.

There are several important problems with the NNT, involving bias and lack of reliable confidence intervals, as well as difficulties in excluding the possibility of no difference between two treatments or groups.

Normal ( non-neoplastic ) prostatic tissue ( NNT ).

Nostalgic Yankee readers of Erskine Caldwell are today informed by proud Georgians that Tobacco Road is buried beneath a four-lane super highway, over which travel each day suburbanite businessmen more concerned with the Dow-Jones average than with the cotton crop.

The average Democratic politician, especially in the country districts, is hungry for the spoils of office.

The national average is more than $4 and that figure is considered by experts in the mental health field to be too low.

Carbondale is in the Herrin-Murphysboro-West Frankfort labor market, where unemployment has been substantially higher than the national average.

But for the average citizen, unfortunately, this is one of science's worst-marked channels, full of tricky currents and unknown depths.

I am firmly convinced that considering the average quality of teachers in this country, the profession is grossly overpaid.

Of these states the average `` change-over '' point ( at which a car is substituted for allowances ) is 13,200 miles per year.

The average of states' rates is $.076 per mile.

Rhode Island's rate of $.07 per mile is considerably lower than reimburseable rates in the federal government and in industry nationally which approximate a $.09 per mile average.

Such payments shall be made to small domestic producers of lead as long as the market price for common lead at New York, New York, as determined by the Secretary, is below 14-1/2 cents per pound, and such payments shall be 75 per centum of the difference between 14-1/2 cents per pound and the average market price for the month in which the sale occurred as determined by the Secretary.

Such payments shall be made to small domestic producers of zinc as long as the market price for prime western zinc at East Saint Louis, Illinois, as determined by the Secretary, is below 14-1/2 cents per pound, and such payments shall be 55 per centum of the difference between 14-1/2 cents per pound and the average market price for the month in which the sale occurred as determined by the Secretary.

With respect to nighttime assignments, the degree of skywave service and interference is determined by skywave curves ( figs. 1 and 2 of sec. 3.190 of the rules ) giving average skywave values.

The minimum cost for an average one-story, 7-room house with basement, is likely to run $1500 above the cost of the heating alone.

This is if outdoor temperatures have a high average of 95 degrees.

You'll need more if the high average is above that, less if it's below.

On this first venture the central storage is 20,000 gallons, in two tanks, or an average of 400 gallons for each of the 50 homes.

The average charge for this additional insurance coverage is roughly $1.00 a day.

It is well to bear in mind that gasoline will cost from $.80 to $.90 for the equivalent of a United States gallon and while you might prefer a familiar Ford, Chevrolet or even a Cadillac, which are available in some countries, it is probably wiser to choose the smaller European makes which average thirty, thirty-five and even forty miles to the gallon.

Your chauffeur's expenses will average between $7.00 to $12.00 a day, but this charge is the same whether you rent a 7-passenger Cadillac limousine or a 4-passenger Peugeot or Fiat 1800.

Since most European cars average more miles per gallon of gasoline than American cars, it naturally follows that the cost per kilometer for these models will be less, but the greater seating capacity of the large American cars will equalize this, provided your group is sufficiently large to fill a 7-passenger limousine.

The ratio of the measured antenna temperature change during a drift scan across the moon to the average brightness temperature of the moon over the antenna beam ( assuming that the brightness temperature of the sky is negligible ) was found, by graphical integration of the antenna directivity diagram, to be 0.85.

If one assumes that the average flux did not change between measurements, a mass-distribution curve is obtained which relates the flux of particles larger than a given radius to the inverse 7/2 power of the radius.