The phrase "are difficult to rectify" is correct and usable in written English.
It can be used when discussing issues or problems that are challenging to correct or resolve.
Example: "The errors in the report are difficult to rectify, requiring extensive revisions."
Alternatives: "are hard to fix" or "are challenging to correct".
Such discordance may be related to recall bias of the TB patient and may be difficult to rectify.
Problems related to the quality of data may be difficult to rectify once data have been collected.
This is difficult to rectify as the Swedish pediatric population diagnosed with cancer is, for natural reasons, small.
This model requires a stable interaction between ran and importins, which is difficult to rectify with the ran-dependent dissociation of importin-cargo complex during nuclear import.
The upper pilosebaceous unit contains multiple overlapping populations of SCs; however, it has been difficult to rectify differing observations between expression studies, lineage-tracing studies, and reporter models (Horsley et al., 2006; Levy et al., 2005; Snippert et al., 2010; Brownell et al., 2011).
Skin bioprinting has the great opportunities to build complex tissue constructs needed to rectify complicated skin defects which are difficult to heal by normal clinical procedures.
It was very difficult to rectify the problem because he had no money to pay for phone calls, and no money for the £4.50 return bus fare from his village to Witney, where the Jobcentre is based.
No other conceptual work is as difficult to rectify at a later stage or as damaging to the overall system if performed incorrectly.
Since most of the supply chain infrastructures are generally widespread and their constructions are expensive and time consuming, it will be very costly and difficult to rectify the design.
In other cases, staff numbers have been reduced to meet fiscal constraints, which subsequently created shortages much more difficult to rectify.
