A common approach is to forecast  by analogy, using data for similar products that have been on the market previously.
( ( A ( common approach ) ) ( ( is ( to ( ( ( forecast ( by analogy ) ) , ) ( using ( ( data ( for ( similar products ) ) ) ( that ( have ( ( been ( on ( the market ) ) ) previously ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (DT A) (JJ common) (NN approach)) (VP (VBZ is) (S (VP (TO to) (VP (VB forecast) (PP (IN by) (NP (NN analogy))) (, ,) (S (VP (VBG using) (NP (NP (NNS data)) (PP (IN for) (NP (JJ similar) (NNS products))) (SBAR (WHNP (WDT that)) (S (VP (VBP have) (VP (VBN been) (PP (IN on) (NP (DT the) (NN market))) (ADVP (RB previously))))))))))))) (. .)))
Using similar product data is commonly used as a forecast method.
( ( Using ( similar ( product data ) ) ) ( ( ( is commonly ) ( used ( as ( a ( forecast method ) ) ) ) ) . ) )
(ROOT (S (S (VP (VBG Using) (NP (JJ similar) (NN product) (NNS data)))) (VP (VBZ is) (ADVP (RB commonly)) (VP (VBN used) (PP (IN as) (NP (DT a) (NN forecast) (NN method))))) (. .)))