extractQuantilesDS1 {dsBase} | R Documentation |

identify the global values of V2BR (i.e. the values across all studies) that relate to a set of quantiles to be evaluated.

extractQuantilesDS1(extract.quantiles, extract.summary.output.ranks.df)

`extract.quantiles` |
one of a restricted set of character strings that fix the set of quantile values for which the corresponding values across all studies are to be estimated. For more details see the associated document entitled "secure.global.ranking.docx", the header for ds.ranksSecure and ds.extractQuantiles functions. The value of this argument is set in choosing the value of the argument <quantiles.for.estimation> in ds.ranksSecure. |

`extract.summary.output.ranks.df` |
character string specifying optional name for the data.frame written to the serverside on each data source that contains 5 of the key output variables from the ranking procedure pertaining to that particular data source. This data frame represents the key source of information - including global ranks - that determines the values of V2BR that are identified as corresponding to the particular set of quantiles to be estimated as specified by the <quantiles.for.estimation> argument of function ds.ranksSecure (and the <extract.quantiles> argument of ds.extractQuantiles). |

Severside aggregate function called by ds.extractQuantiles via ds.ranksSecure. As well as estimating the key values of V2BR that correspond to the selected quantiles, this function also implements a disclosure control trap. If the ratio of the total number of all observations across all studies divided by the number of quantile values to be estimated is less than or equal to nfilter.subset (which specifies the minimum size of a subset) the process stops and an error message is returned suggesting that you might try selecting a narrower range of quantiles with less quantile values to be estimated as specified by the argument <quantiles.for.estimation> of the function ds.ranksSecure. For more details about the cluster of functions that collectively enable secure global ranking and estimation of global quantiles see the associated document entitled "secure.global.ranking.docx"

as a first step in creating the vector of values of values of V2BR that correspond to each quantile value, extractQuantilesDS1 identifies the two closest quantile values across all studies that span each key quantile value. These are saved as the data frame "closest.bounds.df" on the clientside and then saved on the serverside by ds.dmtC2S into the data frame "global.bounds.df". Also if the number of observations across all studies is too small, and a disclosure risk exists if the final.quantile.vector is made available via the client, this function stops the processing and returns a warning/error message.

Paul Burton 11th November, 2021

[Package *dsBase* version 6.2.0 ]