Comparative metrics

Usually the relative values between compared commodities are  discussed in the market  with market participants. The negotiation includes , comparison to the same commodity or comparison to a more  traded but slightly different specification commodity in the same market centre, or comparison to the same commodity traded for a different delivery timing or comparison to the commodity’s primary feedstock or primary derived products. 

Lastly comparison to trade in the same commodity but in a different modality for example a vessel or in a different total volume as in full cargo load versus partial cargo load.