The phrase "appear to be key" is correct and usable in written English.
You can use it when discussing something that seems to be important or essential in a particular context.
Example: "The data from the recent survey appear to be key in understanding customer preferences."
Alternatives: "seem to be crucial" or "seem to be vital."
Even area-wide admissions lotteries - of which the Brighton and Hove system is not - do not appear to be key.
It said that unemployment and changes in the value of the pound appear to be key factors.
Supreme Leader Mr Rouhani would not have been on the list of approved candidates without the support of Ayatollah Ali Khamenei, although there do appear to be key policy differences between the two men.
The greater diversity and numbers of microorganisms on farms appear to be key: these microbial environments prime the innate immunity of infants, conferring protection against both asthma and other allergic diseases.
Either way, and perhaps unsurprisingly, localisation and understanding local market conditions appear to be key.
Compaction and cementation appear to be key factors contributing to the formation of the tight gas sandstone reservoirs.
Uniform dispersion and interfacial adhesion appear to be key factors for improving both sensing and mechanical performance of nanocomposite.
Early changes in microvascular perfusion appear to be key determinants in the reversal of the shock state during resuscitation.
However, we still know little about cocoa pollination ecology and services, although they appear to be key to understand yield functions.
These two appear to be key factors to explain effects or absence of effects and to draw conclusions for the mental health care delivery.
Thus, c-ETS transcription factors appear to be key regulators of MCM4 origin where c-ETS2 seems to promote DNA replication whereas c-ETS1 functions as a negative regulator.
