The hardware and bandwidth for this mirror is donated by dogado GmbH, the Webhosting and Full Service-Cloud Provider. Check out our Wordpress Tutorial.
If you wish to report a bug, or if you are interested in having us mirror your free-software or open-source project, please feel free to contact us at mirror[@]dogado.de.

Dexter

Dexter is an R package for psychometric analysis of data from educational and psychological tests. Dexter typically works with project database files saved on disk.

Installation

install.packages('dexter')

If you encounter a bug, please post a minimal reproducible example on github. We post news and examples on a website and blog.

Example

library(dexter)
# start a project and fill it with data
# verbAggrRules and verbAggrData are example datasets provided with dexter

db = start_new_project(verbAggrRules, "verbAggression.db")
add_booklet(db, verbAggrData, booklet_id = "verb_agg")

# Classical test theory
tia = tia_tables(db)

tia$booklets
booklet_id n_items alpha mean_pvalue mean_rit mean_rir max_booklet_score n_persons
verb_agg 24 0.888 0.339 0.527 0.468 48 316 
head(tia$items)
booklet_id item_id mean_score sd_score max_score pvalue rit rir n_persons
verb_agg S1DoCurse 1.082 0.807 2 0.541 0.582 0.519 316
verb_agg S1DoScold 0.832 0.815 2 0.416 0.651 0.596 316
verb_agg S1DoShout 0.468 0.709 2 0.234 0.520 0.460 316
verb_agg S1WantCurse 1.123 0.827 2 0.562 0.537 0.468 316
verb_agg S1WantScold 0.930 0.850 2 0.465 0.593 0.528 316
verb_agg S1WantShout 0.712 0.777 2 0.356 0.529 0.464 316 
# IRT, extended nominal response model
f = fit_enorm(db)

head(coef(f))
item_id item_score beta SE_beta
S1DoCurse 1 -1.3422140 0.1541565
S1DoCurse 2 -0.6375015 0.1418423
S1DoScold 1 -0.6702036 0.1429057
S1DoScold 2 -0.2589855 0.1579467
S1DoShout 1 0.3254326 0.1480166
S1DoShout 2 0.3687574 0.2099654 
# ability estimates per person
abl = ability(db, parms = f)
head(abl)
booklet_id person_id booklet_score theta
verb_agg dx_0000001 13 -1.0238738
verb_agg dx_0000002 28 0.3124831
verb_agg dx_0000003 4 -2.3748882
verb_agg dx_0000004 19 -0.4630604
verb_agg dx_0000005 7 -1.7721275
verb_agg dx_0000006 25 0.0512826 
# ability estimates without item S1DoScold
abl2 = ability(db, parms = f, item_id != "S1DoScold")

# plausible values

pv = plausible_values(db, parms = f, nPV = 5)
head(pv)
booklet_id person_id booklet_score PV1 PV2 PV3 PV4 PV5
verb_agg dx_0000001 13 -1.1129358 -0.3718473 -0.6251660 -1.0861430 -1.4627665
verb_agg dx_0000002 28 -0.0643628 0.1312981 -0.6255087 -0.1063878 0.3527158
verb_agg dx_0000003 4 -1.8603752 -2.5817701 -1.6376942 -1.7172643 -1.8129040
verb_agg dx_0000004 19 -1.0663677 -0.6810231 -1.1512542 -0.9481833 -0.8004328
verb_agg dx_0000005 7 -2.0083386 -1.5279208 -1.3307093 -1.5430697 -1.3224421
verb_agg dx_0000006 25 0.2020330 0.2050144 0.2221347 -0.4249511 0.0809038

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
Health stats visible at Monitor.