The company, which taps more than 1,000 experts in antiques, fine arts, coins, stamps and other collectibles, gives online estimates of items up for auction for $20 each.
This is of particular concern when parameter estimates of items are going to be treated as known in other applications, for example, in adaptive testing, as part of a calibrated item pool, or for test construction purposes (Davey and Lee 2011; van Barneveld 2007).
Estimates of items such as depreciation, provisions and goodwill are vulnerable to error.
Additionally, no studies have compared reliability estimates of items assessed in different countries, hindering aims towards generalizable park audit items.
The purpose of this study is 1) to describe the development and reliability of a youth-oriented direct-observation park audit tool tested in Montreal, Canada, and; 2) to compare reliability estimates of items with those drawn from a tool previously tested in Perth, Australia, with those same items tested in Montreal, Canada.
The objectives of the current study are therefore twofold: 1) to describe the development and reliability of a youth-oriented direct-observation park audit tool tested in Montreal, Canada, and; 2) to compare reliability estimates of items with those drawn from a tool previously tested in Perth, Australia [ 24, 29], with those same items tested in Montreal, Canada.
Fig. 1 Estimates of item parameters across models.
This may lead to biased estimates of item and person parameters (Mislevy and Wu 1996).
The RMSE and ME values for the estimates of item difficulty were quite small, suggesting that the recovery of the item difficulty parameters was good.
Additionally, all mixture PD models provided relatively similar estimates of item parameters that were different from the parameters estimated by the standard 2PLM.
Major violations of this assumption could lead to biased estimates of item difficulties, thresholds, and further model parameters (Wainer et al. 2007).
