Not exact matches
More disclosure of how
data were handled and reported, and making
data available, can help other scientists spot
false positives in your work.
If the
data yield a P value of.05, the risk of a
false positive is 26 percent, Colquhoun calculates.
Though they can't tell for sure from the
data, the researchers say this suggest that patients who had the thallium scans
were sent for further testing using the invasive angiography technique because the initial scan gave a
false positive for serious blockage.
While there
are a number of portable tests for cocaine commercially available, these
are mainly based on antibody reagents, which can not offer quantitative
data and — since the cocaine antibody can bind to something that
is not cocaine — can give
false positive results.
«
False positives are going to
be random noise rather than systemically biased
data.»
The
data on the numerous candidates
are somewhat preliminary and require validation, but a new analysis by a pair of astrophysicists at the California Institute of Technology suggests that the percentage of
false positives among Kepler's candidate planets may
be less than 10 percent.
Weeding out
false -
positives is one of the greatest challenges facing those of us who analyze massively parallel sequencing
data.
The transit signals
were detected in photometric
data from the Kepler satellite, and
were confirmed to arise from planets using a combination of large transit - timing variations, radial - velocity variations, Warm - Spitzer observations, and statistical analysis of
false -
positive probabilities.
Available
data suggest few SNP alleles can pass the genome - wide multiple testing criteria and the
false positive rate
is very high.
Unfortunately, indels
are both the strength and the weakness of 454
data — due to the underlying pyrosequencing, homopolymeric regions
are often under - or over-called, resulting in numerous
false positives.
A combination of sequencing
data from two different platforms, as suggested by Nothnagel et al. [5] for the reduction of
false positives in newly identified SNVs,
is only of limited use for combining the strengths in coverage of different genomic regions.
Data filtering criteria based on the cross correlation score (Xcorr) and delta correlation (ΔCn) values along with tryptic cleavage and charge states were developed using the decoy database approach and applied for filtering the raw data to limit false positive identifications to < 1 % at the peptide level [22]--[
Data filtering criteria based on the cross correlation score (Xcorr) and delta correlation (ΔCn) values along with tryptic cleavage and charge states
were developed using the decoy database approach and applied for filtering the raw
data to limit false positive identifications to < 1 % at the peptide level [22]--[
data to limit
false positive identifications to < 1 % at the peptide level [22]--[24].
To
be fair, however, with all the
data rolling in,
is it not best to
be conservative and limit the number of «
false positives» that creep out?
For the LTQ - Orbitrap Velos
data, the distribution of mass deviation (from the theoretical masses)
was first determined as having a standard deviation (σ) of 2.05 part per million (ppm), and a mass error of smaller than 3σ
was used in combination with Xcorr and ΔCn to determine the filtering criteria that resulted in < 1 %
false positive peptide identifications.
A
false positive rate of < 4 %
was estimated for each of the LC -
MS data sets.
The algorithm uses the last 1000
data points to not only identify sales, but also try and throw out
false positives (when sales rank changes a small amount not due to sales but due to Amazon adjusting the «list» of books
being ranked in that category).
To reduce the background (e.g., reduce
false positives), it
is necessary to collect SNP array
data for additional EPI - affected and normal GSDs.
The re-sampling process used to generate the 50
data sets
was done to minimize exposure to
false positive declarations of significant departures from an OR of 1.0.
However, persistent cloud cover
is a continuous issue in the tropics, and extreme flooding can also produce unreliable remotely sensed
data that will result in tree cover loss «
false positives» (alerts where no actual tree cover loss has occurred).
Critique 1) I have no idea about any cleansing, homogenisation or aggregation performed on this
data prior to its presentation by Rutgers 2) Snow extent
is only 1 part of the issue, thickness and mass would need to
be considered for a full picture 3) I haven't taken care to provide exactly similar sample sizes, however the F and t methods do not require it 4) I haven't taken care to ensure that the same number of winter periods
are present in each sample batch; this would increase the risk of a
false positive and would have required further investigation if a weak indication of significance had
been detected.
Technology has long
been used to improve user comprehension of
data, but also
is prone to oversimplification of the
data and a propensity for
false positives due to artificial artifacts.
Many of the scales demonstrated weak psychometrics in at least one of the following ways: (a) lack of psychometric
data [i.e., reliability and / or validity; e.g., HFQ, MASC, PBS, Social Adjustment Scale - Self - Report (SAS - SR) and all perceived self - esteem and self - concept scales], (b) items that fall on more than one subscale (e.g., CBCL - 1991 version), (c) low alpha coefficients (e.g., below.60) for some subscales, which calls into question the utility of using these subscales in research and clinical work (e.g., HFQ, MMPI - A, CBCL - 1991 version, BASC, PSPCSAYC), (d) high correlations between subscales (e.g., PANAS - C), (e) lack of clarity regarding clinically - relevant cut - off scores, yielding high
false positive and
false negative rates (e.g., CES - D, CDI) and an inability to distinguish between minor (i.e., subclinical) and major (i.e., clinical) «cases» of a disorder (e.g., depression; CDI, BDI), (f) lack of correspondence between items and DSM criteria (e.g., CBCL - 1991 version, CDI, BDI, CES - D, (g) a factor structure that lacks clarity across studies (e.g., PSPCSAYC, CASI; although the factor structure
is often difficult to assess in studies of pediatric populations, given the small sample sizes), (h) low inter-rater reliability for interview and observational methods (e.g., CGAS), (i) low correlations between respondents such as child, parent, teacher [e.g., BASC, PSPCSAYC, CSI, FSSC -
R, SCARED, Connors Ratings Scales - Revised (CRS -
R)-RSB-, (j) the inclusion of somatic or physical symptom items on mental health subscales (e.g., CBCL), which
is a problem when conducting studies of children with pediatric physical conditions because physical symptoms may
be a feature of the condition rather than an indicator of a mental health problem, (k) high correlations with measures of social desirability, which
is particularly problematic for the self - related rating scales and for child - report scales more generally, and (l) content validity problems (e.g., the RCMAS
is a measure of anxiety, but contains items that tap mood, attention, peer interactions, and impulsivity).
These changes
are effectively skewing results to the
positive side and creating a
false, misleading and inaccurate representation of the Calgary market that
is causing Calgarians to make financial decisions based on
false MLS
data.