Using OSPD (Scrabble dictionary) and running a search on words:
CEI is the way it should be after a C, because after a C the I before E rule does not apply.
CEILINGS CEINTURE CONCEITS CONCEIVE CROCEINE CROCEINS DECEIVED DECEIVER DECEIVES ENCEINTE GLACEING NARCEINE NARCEINS PERCEIVE RECEIPTS RECEIVED RECEIVER RECEIVES CADUCEI CEILERS CEILING CONCEIT CROCEIN DECEITS DECEIVE NARCEIN ORCEINS RECEIPT RECEIVE CEIBAS CEILED CEILER DECEIT ORCEIN CEIBA CEILS CEIL
37 words found
So how many exceptions are there to this rule? How often it it 'I' before 'E' regardless of 'C'?
ABBACIES ACIERATE AGENCIES ANCIENTS BOUNCIER CHANCIER CURACIES DIOECIES FACIENDS FANCIERS FANCIEST FLEECIER GLACIERS HACIENDA IDIOCIES JOUNCIER JUICIEST LANCIERS LEGACIES LUNACIES MINCIEST NESCIENT PAPACIES PIRACIES POLICIES PRECIEUX PRICIEST SAUCIEST SCIENCES SOCIETAL SPACIEST SPICIEST SPRUCIER ANCIENT BOCCIES DICIEST FACIEND FANCIED FANCIER FANCIES FARCIES GLACIER JUICIER LACIEST MERCIES MINCIER NANCIES PRICIER RACIEST SAUCIER SCIENCE SOCIETY SPACIER SPECIES SPICIER BOCCIE DICIER FACIES FARCIE ICIEST LACIER RACIER SPECIE ICIER
64 words found
There are 64 exceptions to a rule that applies to 37 words.
Scrabble.com has words with CEI (the rule sanctioned version).
CADUCEUS [13 pts] , (CADUCEI)
a heraldic wand or staff -- CADUCEAN
RECEIVER [13 pts] , (RECEIVERS)
one that receives
24 words found.
And for CIE (the exceptions):
ABBACY [15 pts] , (ABBACIES)
the office of an abbot
VIBRANCY [18 pts] , (VIBRANCIES)
the quality or state of being vibrant
167 words found.
THE DAMNED RULE APPLIES TO 24 WORDS AND HAS 167 EXCEPTIONS!
The rule should say I before E, 92% (400 EI vs 5000 IE) of the time, and I before E even after a C around 85% of the time.
It gets even dumber. Consider things like I before E except after S. There's 38 examples of SEI and only 237 exceptions (SIE) which is a solid 16% correct. Which is a bit better than the rule with the C in it, which is only right 14% of the time applying to 24 words and having 167 exceptions. With 'H' you can get 39 applications with 228 exceptions for 17% application. The real clincher is 'E'. I before E except after E applies 39 times and is wrong 0 times. There are 39 'EEI' words and 0 'EIE' words.
There you go. I before E except after E.