Once in process an application will not be returned as incomplete. That does not foretell how the application will fare on the merits, but only means that the application will go through the processing and IRCC will make a determination as to whether to grant citizenship.
In a macro sense, the item regarding tax filing history is straight-forwardly about making sure the applicant met the current citizenship requirement: that for four of the relevant tax years, the applicant complied with CRA tax filing requirements.
Any year in which the applicant was not required to file taxes will count toward the four, whether a return was filed or not. For any year in which filing a return was required, the applicant needs to have filed a return for that year to count. Years that count need to add up to a total of four (of the potential six years). Thus, if the manner in which the applicant completed this item shows compliance with CRA requirements for four of the relevant years, that satisfies this qualifying element.
Beyond that, however, any and all information in the application can be examined, considered, and compared to other information, for a variety of purposes. The most obvious one for the tax item is that how the applicant responded will likely be reviewed to discern whether that response is consistent with the applicant's reported employment history . . . an applicant reporting full time employment in Canada for a year but responding "no" as to whether a return was required that year, is bound to attract some negative scrutiny.
Remember, what actually happens during processing can vary considerably depending on many, many factors. And how the applicant responded to the item regarding tax filings is, of course, part of the information which IRCC will consider, including in context with other information. And, again, if there is an inconsistency between how the applicant completed this item and CRA records, that may be identified by CRA and brought to the attention of IRCC. (Actual extent and manner of sharing is largely unknown, but the law, including regulations, are in place to facilitate IRCC sharing the tax item responses with CRA and CRA in turn sharing with IRCC any inconsistencies with their records.)
In a macro sense, the item regarding tax filing history is straight-forwardly about making sure the applicant met the current citizenship requirement: that for four of the relevant tax years, the applicant complied with CRA tax filing requirements.
Any year in which the applicant was not required to file taxes will count toward the four, whether a return was filed or not. For any year in which filing a return was required, the applicant needs to have filed a return for that year to count. Years that count need to add up to a total of four (of the potential six years). Thus, if the manner in which the applicant completed this item shows compliance with CRA requirements for four of the relevant years, that satisfies this qualifying element.
Beyond that, however, any and all information in the application can be examined, considered, and compared to other information, for a variety of purposes. The most obvious one for the tax item is that how the applicant responded will likely be reviewed to discern whether that response is consistent with the applicant's reported employment history . . . an applicant reporting full time employment in Canada for a year but responding "no" as to whether a return was required that year, is bound to attract some negative scrutiny.
Remember, what actually happens during processing can vary considerably depending on many, many factors. And how the applicant responded to the item regarding tax filings is, of course, part of the information which IRCC will consider, including in context with other information. And, again, if there is an inconsistency between how the applicant completed this item and CRA records, that may be identified by CRA and brought to the attention of IRCC. (Actual extent and manner of sharing is largely unknown, but the law, including regulations, are in place to facilitate IRCC sharing the tax item responses with CRA and CRA in turn sharing with IRCC any inconsistencies with their records.)
