As the number of letters in a word decreases, the number of ladders increase sharply, despite there being only one-tenth the number of four-letter words as there are ten-letter words. The sharply increased number means that more and more restrictions may be applied but still ladders can be found. The following table summarizes this effect. Looking down a column, it can be seen that decreasing the word length by one multiplies the number of ladders of a given type by hundreds of times.
Word Ways: Vol. 34
, Article 15.
Available at: http://digitalcommons.butler.edu/wordways/vol34/iss2/15