Hi David,

Thanks for your kind help. Actually I am estimating the FDR by using the
Mayu tool, after combining the iprophet results of all the three datasets
which I have, as this gives me single Posterior probability (PPs/IPs) that
I am using in the SpectraST command line so as to generate the spectral
library.
Yes, I got the point which you have highlighted, but can I use Mayu for
estimating the FDR at final stage and then filter the results below the
threshold PP of FDR less than 1%, instead of filtering the results at each
iProphet analyses?

Thanks
Ankit




On Fri, 5 Apr 2019 at 20:03, David Shteynberg <
[email protected]> wrote:

> Hello Ankit,
>
> If you computer has the resources to handle all files then running one
> iProphet job to combine the results will give you one analysis result with
> FDR rates that apply to all the data.  If you do multiple iProphet runs
> then you have to be more careful about how you combine the results because
> your runs will overlap more in the correct result than the incorrect
> results so simply taking all results together above an FDR threshold will
> inflate your final FDR.  One easy way to do this is to divide the FDR by
> the number of iProphet runs being combined.  For example if you split the
> results into two iProphet analyses and you want the combined FDR to be less
> than 1% you would filter each iProphet analyses at 0.5% FDR and then take
> the total set.  Does that make sense?
>
> Cheers,
> -David
>
> On Thu, Apr 4, 2019 at 8:57 AM Ankit Balhara <[email protected]>
> wrote:
>
>> Thanks Felipe.
>>
>> I have posted this issue in the issues section of DIA-Umpire issue
>> tracker.
>>
>> Ankit
>>
>>
>>
>> On Thu, 4 Apr 2019 at 19:21, Felipe da Veiga Leprevost <
>> [email protected]> wrote:
>>
>>> Hi Ankit;
>>>
>>> Please feel free to submit your DIA-Umpire questions and issues to our
>>> DIA-Umpire issue tracker: https://github.com/Nesvilab/DIA-Umpire
>>>
>>> Regards
>>>
>>> On Wednesday, April 3, 2019 at 7:05:59 AM UTC-4, Ankit Balhara wrote:
>>>>
>>>> Hi All,
>>>>
>>>> I am analyzing the SWATH-MS data using the DIA-Umpire. And I have 3
>>>> data files of same sample which lead to generation of 9 .mgf output files
>>>> from DIA-Umpire, which were converted into 9 mzXML and then subjected to
>>>> Comet and X! Tandem search, and subsequently to peptide prophet and hence
>>>> total files generated during this process are 18 pep.xml files.
>>>> My ultimate aim to build the assay library. So, I am confused how to
>>>> combine the results of these 18 peptideprophet files.
>>>>
>>>> Should I combine the Comet search results of each data file separately
>>>> and X! Tandem results separately and then combine these outputs again using
>>>> iProphet? This should result in generation of 3 iprophet result files
>>>> corresponding to each data file, which can again combined into one file by
>>>> iProphet in final step?
>>>>
>>>> Or there is another way out of this problem?
>>>>
>>>> Thanks
>>>>
>>>> Ankit
>>>>
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