the key insight in this algorithm is that if the end of the pattern is compared to the text, then jumps along the text can be made rather than checking every character of the text. the reason that this works is that in lining up the pattern against the text, the last character of the pattern is compared to the character in the text. if the characters do not match, there is no need to continue searching backwards along the text. if the character in the text does not match any of the characters in the pattern, then the next character in the text to check is located characters farther along the text, where is the length of the pattern. if the character in the text "is" in the pattern, then a partial shift of the pattern along the text is done to line up along the matching character and the process is repeated. jumping along the text to make comparisons rather than checking every character in the text decreases the number of comparisons that have to be made, which is the key to the efficiency of the algorithm.