Cause, condition and effect in Buddhism If the result of one's karma is the combination of cause and condition, how does one account for all variables in the culmination of an effect? 

If one is unable to include all variables, isn't that simply a limited view of the effect?
As others have mentioned it's not recommended to attempt to account for all the variables in karmic effects. Here is the basis for this. It's the third on a short list of what is called the Four Imponderables or Unconjecturables:

&quot;There are these four unconjecturables that are not to be conjectured about, that would bring madness &amp; vexation to anyone who conjectured about them. Which four?
&quot;The Buddha-range of the Buddhas1 is an unconjecturable that is not to be conjectured about, that would bring madness &amp; vexation to anyone who conjectured about it.
&quot;The jhana-range of a person in jhana...2
&quot;The [precise working out of the] results of kamma...
&quot;Conjecture about [the origin, etc., of] the world is an unconjecturable that is not to be conjectured about, that would bring madness &amp; vexation to anyone who conjectured about it.
&quot;These are the four unconjecturables that are not to be conjectured about, that would bring madness &amp; vexation to anyone who conjectured about them.&quot;

From Acintita Sutta: Unconjecturable
But while pondering the precise effects of karma is not something a person working toward Nirvana should do, as it's a distraction; a fully enlightened Buddha would know such effects.

&quot;When the mind was thus concentrated, purified, bright, unblemished, rid of defilement, pliant, malleable, steady, &amp; attained to imperturbability, I directed it to the knowledge of the passing away &amp; reappearance of beings. I saw — by means of the divine eye, purified &amp; surpassing the human — beings passing away &amp; re-appearing, and I discerned how they are inferior &amp; superior, beautiful &amp; ugly, fortunate &amp; unfortunate in accordance with their kamma: 'These beings — who were endowed with bad conduct of body, speech &amp; mind, who reviled the Noble Ones, held wrong views and undertook actions under the influence of wrong views — with the break-up of the body, after death, have re-appeared in the plane of deprivation, the bad destination, the lower realms, in hell. But these beings — who were endowed with good conduct of body, speech, &amp; mind, who did not revile the Noble Ones, who held right views and undertook actions under the influence of right views — with the break-up of the body, after death, have re-appeared in the good destinations, in the heavenly world.' Thus — by means of the divine eye, purified &amp; surpassing the human — I saw beings passing away &amp; re-appearing, and I discerned how they are inferior &amp; superior, beautiful &amp; ugly, fortunate &amp; unfortunate in accordance with their kamma.

From Dvedhavitakka Sutta: Two Sorts of Thinking