Psychometric Properties of a Persian-Language Version of the Obsessive-Compulsive Inventory-Revised: OCI-R-Persian

doi:10.4236/psych.2011.23032

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Psychology

2011. Vol.2, No.3, 210-215

Psychometric Properties of a Persian-Language

Version of the Obsessive-Compulsive Inventory-Revised:

OCI-R-Persian

Habibollah Ghassemzadeh1*, Giti Shams1, Jamal Abedi2, Narges Karamghadiri1,

Narges Ebrahimkhani1, Mansoureh Rajabloo3

1Roozbeh Hospital, Department of Psychiatry Tehran University of Medical Sciences, Tehran, Iran;

2School of Education, University of California, Davis, USA;

3Private practice, Tehran, Iran.

*Email: [email protected]

Received October 17th, 2010; revised March 4th, 2011; accepted April 5th, 2011.

The psychometric properties of the Persian-language version of Obsessive-Compulsive Inventory-Revised

(OCI-R) were studied in a sample of Iranian college students (N = 450). The total and each of the subscales of

OCI-R-Persian demonstrated very high internal consistency as well as high test-retest reliability. Convergent and

divergent validity of the OCI-R-Persian total scale and subscales were satisfactory. In general, the

OCI-R-Persian appears to be a reliable and valid measure of obsessive-compulsive symptoms in this non-clinical

sample of Iranian college students.

Keywords: Confirmatory Factor Structure, OCD, OCI-R-Persian, Psychometric Properties

Introduction

The utility of using psychological measures of obsessive-

compulsive disorder (OCD) in both research and clinical set-

tings is widely recognized (Goodman and Price, 1998; St. Clare,

2003). Many of these measures are based on self-report of

symptoms. In a review of different self report measures, Foa,

Kozak and Salkovskis (1998) addressed some of the problems

and limitations inherent in such instruments as Yale-Brown

Obsessive-Compulsive Scale (YBOCS; Goodman et al., 1989),

Layton Obsessional Inventory (LOI; Taylor, 1995), the Com-

pulsive Activity Checklist (CAC; Cottraux et al., 1988), and the

Maudsley Obsessive-Compulsive Inventory (MOCI; Hodgson

& Rachman, 1977). Based on their critical review, Foa and her

colleagues (1998) introduced a new obsessive-compulsive dis-

order scale called the Obsessive-Compulsive Inventory (OCI).

This scale consists of 42 items grouped in seven subscales

(checking, washing, obsessing, mental neutralizing, ordering,

hoarding and harming, and doubting). The subscales are further

divided up into frequency and distress dimensions.

The OCI showed “excellent” internal consistency and “satis-

factory” test-retest reliability for both symptom frequency and

associated distress in individuals with OCD and in non-patient

controls. The coefficient alphas for OCI total score in OCD

group were .93 for frequency and .92 for distress. The same

coefficients were .94 and .95 in control group. The test-retest

reliabilities for OCI total score in OCD group were .84 for fre-

quency and .87 for distress. The same coefficients were .90

and .89 in control group (Foa et al., 1998). These researchers

further introduced a revised shorter version of the OCI, the

OCI-R. Several considerations led to the revision: 1) there was

a high correlation between the distress and frequency total

score (above .90) in the original OCI, indicating redundancy in

the two scales; 2) the time needed for the completion of OCI

made it somewhat difficult to use in the clinical and/or hospital

settings; and 3) the number of items varied across scales in the

original OCI. The OCI-R consists of 18 items, yielding six

subscales: washing, checking, ordering, obsessing, hoarding,

and neutralizing. It is significantly shorter than OCI, and elimi-

nates the frequency scale. Each subscale has three items which

are summed up, facilitating comparisons across scales. The

psychometric properties of the OCI-R were assessed by Foa and

her colleagues (2002). The subsequent studies have provided

further support for the psychometric properties of OCI-R in both

clinical and non-clinical samples (e.g., Hajcak et al., 2004;

Abramowitz & Deacon, 2006; Smari et al., 2007).

OCD Measures in Iran

A number of instruments for assessment of OCD symptoms

have been previously translated into Persian (Farsi) and used in

Persian speaking patient and non-patient populations. In an

earlier study (Ghassemzadeh et al., 2002) we examined the

symptoms in a sample of Iranian OCD patients using Persian

translations of the Maudsley Obsessional-Compulsive Inven-

tory (MOCI) and Compulsive Activity Checklist (CAC). In our

study, the mean scores on MOCI (M = 15.73, SD = 5.63) and

CAC (M = 14.90, SD = 9.77), were close to those reported in

other settings. However, we encountered numerous problems in

using MOCI in this setting. First, some of the items were not

easily understood by the patients, especially the double-nega-

tive sentences (e.g. “I don’t worry unduly about contamination

if I touch an animal.”). Second, the true-false response format

of MOCI made it difficult for many indecisive patients to re-

spond. Third, as Foa et al. (1998) suggested the items of the

MOCI encompass only two of the behavioral compulsions (i.e.

H. GHASSEMZADEH ET AL. 211

checking and washing) and do not measure specific obsessions

other than contamination. These difficulties with MOCI moti-

vated us to translate and examine the feasibility of the OCI-R in

the Iranian culture. In our preliminary work, we found OCI-R

practical and easily understood by most respondents. Having

fewer items than MOCI, using a 5-point Likert scale response

format, and equal number items for every subscale are other

important aspects of OCI-R. In this report, we present the re-

sults of a study of the psychometric properties and construct

validity of the Persian translation of the OCI-R in a sample of

450 Iranian male and female college students.

Method

Participants

The sample consisted of 450 (164 males and 286 females)

student volunteers recruited from Tehran University of Medical

Sciences and Allameh Tabatabai University, both in Tehran,

Iran. The average age of the total sample was 22.12 (SD = 3.95)

for males and 22.83 (SD = 3.53) for females.

Measures

Obsessive-Compulsive Inventory-Revised (OCI-R)

The OCI-R is an 18-item instrument developed based on the

earlier 42-item version (Foa, Kozak, & Salkovskis et al., 1998;

Foa, Huppert, & Leiberg et al., 2002). The OCI-R comprises

six scales: (1) Washing, (2) Checking/doubting, (3) Obsessing,

(4) Mental neutralizing, (5) Ordering, and (6) Hoarding. Each

item is rated on a five-point (0 - 4) Likert scale for distress or

bother during the past month. The total score ranges from 0 to 72.

The original English version of OCI-R was obtained from Dr.

Edna Foa at the University of Pennsylvania and translated to

Persian by the first author (H. G.). The Persian draft was then

back-translated by a professional bilingual translator. The back

translated version was then sent to one of the colleagues of Dr.

Foa who reviewed the English text and provided suggestions to

improve the accuracy of the Persian translation. After incorpo-

rating those points in the translation and going through to the

process of second back translation, the final version of OCI-R

Persian was ready to use in our sample.

Mausley Obsessional-Compulsive Inventory

(MOCI)-Persian version

The MOCI is a 30-item true-false instrument for assessment

of OCD symptoms. Maximum scores for the five scales (total,

checking, washing, slowness-repetition, and doubt-conscien-

tious) are 30, 9, 11, 7, and 7, respectively. This inventory has

been used with adequate validity and reliability (Rachman &

Hodgson, 1980). The Persian language version of the test has

been used in a number of studies in Iran (Ghassemzadeh, 2002,

2005a, 2005b).

Compulsive Activity Checklist (CAC)

The original format of this inventory had 62 items concern-

ing specific daily activities rated on a 4-point scale of severity.

We used a French version of CAC, which is an abbreviated

form of the instrument and contains 19 items centered mainly

on checking behavior and rituals (Cottraux et al., 1988). Each

item is rated on a four-point (0 - 3) scale, therefore the scores

range from 0 to 57. Different versions of CAC have demon-

strated good internal consistency (St. Clare, 2003). This test has

been translated into Persian and used in our previous studies in

Iran (Ghassemzadeh et al., 2002, 2005b).

Beck Depression Inventory-II- Persian Version

BDI-II is the second edition of the widely used 21-item in-

ventory, the BDI. Originally developed in 1960s (Beck et al.,

1961), BDI-II was revised to approximate the DSM-IV criteria

for major depression. Scores on each item range from 0 to 3,

yielding a possible maximum total score of 63. The Persian

version of this test (BDI-II- Persian) is widely used in various

settings in Iran. Its psychometric properties have been exam-

ined elsewhere (Ghassemzadeh, et al., 2005c).

Procedure

All the tests were administered to the students in a group set-

ting during a class session after a brief description of the pur-

pose of the study. The students were told that the participation

is voluntary and no payment or course credit was offered to the

participants. The OCI-R was administered first, followed by

MOCI, CAC and BDI-II. All the assessments were repeated in

the same sample after 2 weeks. Due to some logistical issues,

MOCI, CAC and BDI-II were administered only to 228 sub-

jects of the total sample.

Results

Descriptive Statistics of the OCI-R Scale and

Subscales

The means and standard deviations on the OCI-R (total and

subscales) for males and females (separately and total) are pre-

sented in Table 1.

As the data in Table 1 show, female students generally

scored higher than males on most subscales. However, the dif-

ference reached a statistically significant level only on the “ob-

sessing” subscale (t = 2.27, df = 448, P < .05).

Table 2 shows the mean scores obtained in the present study

as compared with Foa’s group (2002). Our mean score for the

whole group is very close to their mean score (18.46 vs. 18.82).

This is true for some subscales but with some considerations.

Since Foa’s group was regarded as non-anxious control and our

group as normal college students, it would be difficult to com-

pare the results of these two studies.

Correlations amon g O CI-R Subscal es

Correlations between each of the subscales and the total scale

of the OCI-R as well as the inter-correlations among the sub-

scales are shown in Table 3. Correlations between each of the

subscales and the total scale ranged from .63 (ordering) to .76

(obsessing). Inter-correlations among the subscales ranged

from .21 (neutralizing & ordering) to .51 (hoarding & obsess-

ing). All the correlations were significant at .01 level.

Test-Retest Reliability and Internal Consistency

The two-week test-retest reliability was calculated using

Pearson’s r correlation coefficients. Cronbach’s alpha was cal-

culated and used to assess the internal consistency of the OCI-R

H. GHASSEMZADEH ET AL.

212

Table 1.

Scores on the OCI-R scale a mo n g 450 f e m a l e a n d m a l e Iran i a n c ol l e g e s t udents.

Total

(N = 450)

Females

(N = 286)

Males

(N = 164)

(df = 448)

OCI-R

M S.D. M S.D. M S.D.

Checking 2.38 2.26 2.42 2.35 2.32 2.09 .45

Hoarding 3.49 2.49 3.59 2.59 3.30 2.30 1.18

Neutralizing 1.09 1.74 1.11 1.72 1.07 1.79 .24

Ordering 5.16 2.87 5.13 2.96 5.22 2.70 −.33

Washing 2.19 2.21 2.24 2.28 2.11 2.09 .59

Obsessing 4.15 2.90 4.38 3.01 3.74 2.65 2.27*

Total 18.46 9.92 18.86 10.44 17.76 8.93 1.13

*p < .05.

Table 2.

The mean and SD s cores of OCI -R (total and su bscales) in the prese nt study a nd Foa’s me an and SD scor es for non- anxiou s contr ols (NACs).

Foa’s group

(N = 477)

Present study

(N = 450)

OCI-R

M S.D. M S.D.

Checking 2.91 2.56 2.38 2.26

Hoarding 4.41 2.67 3.49 2.47

Neutralizing 1.82 2.20 1.09 1.74

Ordering 4.40 3.03 5.16 2.87

Washing 2.41 2.50 2.19 2.21

Obsessing 2.86 2.72 4.15 2.90

Total 18.82 11.10 18.46 9.92

Table 3.

Correlations between OCI-R subscales and total scale and inter -correlations among th e su bscales.

OCI-R Checking Hoarding Neutralizing Ordering Washing Obsessing

Total

Checking 1 .47 .26 .31 .48 .49

.73

Hoarding 1 .32 .29 .41 .51

.73

Neutralizing 1 .21 .22 .31

.51

Ordering 1 .36 .29

.63

Washing 1 .42

.70

Obsessing 1

.76

Total

All p-value < .01.

total scale, as well as the subscales (Table 4). The OCI-R total

scale as well as its subscales demonstrated very high test-retest

correlations and internal consistency.

Convergen t a nd Divergent Val i di ty of the OCI-R

Total Scale and Subscales

Convergent validity of OCI-R total scale was determined by

correlating the OCI-R with two other measures of obsessive-

compulsive symptoms, the MOCI and CAC, which have been

used in the previous studies of OCD in this setting (Ghas-

semzadeh et al., 2002, 2005a). The correlations between the

OCI-R total and subscale scores with MOCI total, washing and

checking subscales are presented in Table 5.

The MOCI and the CAC total scores correlated .571 and .475,

H. GHASSEMZADEH ET AL. 213

respectively with OCI-R, indicating moderate convergent

validity.

Correlations of OCI-R checking and washing subscales with

corresponding subscales of MOCI were .558 and .338, respec-

tively. But the highest correlation (.575) was related to MOCI

total score with OCI-R checking subscale. Correlations among

different subscales of OCI-R and MOCI washing and checking

subscales varied from .130 to .575.

The divergent validity of OCI-R was assessed by correlating

the OCI-R total and subscale scores with BDI-II (Table 6). The

correlation between OCI-R total and BDI-II as a distinct meas-

ure from OCD was .398, indicating a lower correlation than the

convergent validity.

Factor Structure of OCI-R-Persian

A confirmatory factor analytic model was used to examine

the conceptual structure underlying the OCI-R, the Persian

version. These analyses were conducted using EQS software

(Bentler, 1992). Two SEM models were created. In the first

model all the subscales include 3 items- the same as Foa’s (Foa

et al., 2002) findings except “neutralizing” which includes 2

items (item 16 was excluded) and washing which includes 4

items (item 16 was added to this subscale). Item 16 in the

original Foa’s scale was part of the “neutralizing” subscale.

Table 4.

Test-retest reliability and internal consistency coefficients for OCI-R

total scale and subscales.

OCI-R Test-retest Cronbach’s alpha

Checking .70 .82

Hoarding .73 .84

Neutralizing .62 .77

Ordering .69 .82

Washing .66 .80

Obsessing .76 .86

Total .75 .85

Table 5.

Convergent validity for the OCI-R-Persian subscale and total scores.

MOCI

(N = 228)

CAC

(N = 228)

OCI-R

(N = 450)

Total Washing Checking Total

Checking .575 .314 .558 .359

Hoarding .378 .193 .291 .365

Neutralizing .191 .130 .185 .275

Ordering .223 .184 .137 .111

Washing .394 .338 .333 .412

Obsessing .524 .300 .527 .397

Total .571 .365 .506 .475

Table 6.

Divergent Validity for OCI-R- Persian.

OCI-R

(N = 450)

BDI-II

(N = 228)

Checking .381

Hoarding .244

Neutralizing .146

Ordering .137

Washing .203

Obsessing .457

Total .398

Alternatively, the second model included item 16 in the “neu-

tralizing” subscale as was originally suggested by Foa. Table 7

presents the results of SEM analyses for Model 1 and Table 8

reports the results for Model 2. For both models, we have as-

sessed all the fit indices reported in the SEM literature includ-

ing Normed Fit Index (NFI), Comparative Fit Index (CFI),

Joreskog-Sorbom’s GFI and standardized Root Mean-Square

Residuals (SRMR) (Bentler & Bonett, 1980; Bollen, 1989). As

it can be seen from both Tables 7 and 8, these fit indices are all

at the satisfactory level and suggest a good fit of the data to the

models. For model 1 the NFI is .876 and the GFI for this model

is .928 both suggesting a good fit. Similarly, for model 2, the

NFI is .876 and the GFI is .929 almost identical with the fit

indices of Model 1. Other fit indices reported for the two mod-

els are also almost identical suggesting that both models fit

equally to the data: CFI = .919 for both models; SRMR = .049

(model 1) and .054 (model 2); RMSEA = .060 for both models.

It is usually believed that NFI, CFI, and GFI values of .90 or

greater and SRMR and RMSEA values of .10 or less are mark-

ers of an acceptable fit (Hu & Bentler, 1999). These values in

our study are in an acceptable range.

However, examination of the factor structure of the two

models reveals that item 16 does not fit well under any of the

two models. In fact, this item has the lowest loading with its

latent variable (“ordering” or “neutralizing”) than any other

items with their respective latent variables in both models. This

item does not share a common variance with many other items

included in the inventory. Therefore, it does not make much

difference to include it in either “ordering” or “neutralizing”

subscales. There might be some issue with this item, which will

be considered in discussion section.

Considering the fact that our results, in general, support the

original subscales developed by Foa’s group (2002), we ana-

lyzed our data based on a six-factor model.

Discussion

Overall, the OCI-R appears to have excellent psychometric

properties in this relatively large sample of Iranian college stu-

dents. This finding is consistent with those from a number of

earlier studies examining the psychometric properties of OCI-R

in non-clinical samples from the US (Foa et al., 2002; Hajcak et

al., 2004), Spain (Fullana et al., 2005), and Iceland (Smari et al.,

H. GHASSEMZADEH ET AL.

214

2007). Our work extends this line of investigation by examin-

ing the psychometric properties of OCI-R in a non-Western

setting.

The OCI-R-Persian has excellent internal consistency (alpha

ranges from .77 to .86) and test-retest reliability (correlations

ranges from .62 to .76). The correlations between subscales and

total scale vary between .51 and .76, indicating a large correla-

tion. But inter-correlations between the subscales were only

moderate. The lowest inter-correlations were related to neutral-

izing. The test-retest reliability for total scale was .75. Although

the coefficients were smaller than Foa’s group (2002),

Table 7.

Model 1, with 6 factors, item 16 loading on “ordering”.

Factors (Subscales) Questions Factor Structures

1. Checking

Q14

Q 2

Q 8

.663

.706

.594

2. Hoarding

Q 7

Q 1

Q13

.686

.607

.685

3. Neutralizing Q 4

Q10

.742

.832

4. Ordering

Q16

Q 3

Q15

Q 9

.276

.797

.802

.631

5. Washing

Q17

Q 5

Q11

.604

.474

.626

6.Obsessing

Q 6

Q12

Q18

.653

.782

.775

Table 8.

Model 2, with 6 factors, item 16 loading on “neutralizing”.

Factors (Subscales) Questions Factor Structures

1. Checking

Q14

Q 2

Q 8

.661

.707

.594

2. Hoarding

Q 7

Q 1

Q13

.686

.609

.684

3. Neutralizing Q 4

Q10

.269

.793

4. Ordering

Q16

Q 3

Q15

Q 9

.774

.799

.800

.632

5. Washing

Q17

Q 5

Q11

.596

.472

.631

6. Obsessing

Q 6

Q12

Q18

.655

.782

.774

all of them indicated excellent test-retest reliability. Our test-

retest reliabilities were in general somewhat higher than the

scores reported in Hajcak’s et al. (2004). For example, their

obtained value for total scale was .70, which was lower than

our value (.75). But their reported values for washing, checking

and obsessing were somewhat higher than our values. Fullana’s

et al. (2005) obtained a test-retest reliability of .67 which is

lower than our value. Their obtained scores for the subscales

were also smaller than our scores.

Similar to other studies (e.g. Fullana, et al., 2005), we found

that OCI-R correlated strongly with other measures of OCD

symptoms (such as MOCI and CAC). Satisfactory convergent

validity is indicated by positive correlation of OCI-R-Persian

total score with the total scores of MOCI and CAC (.571

and .475, respectively). Furthermore, the checking subscale of

the OCI-R-Persian and MOCI was also positively correlated (r

= .558), but the correlation between two washing subscales of

OCI-R-Persian and MOCI was not very high (r = .338). This

may be partly related to the emphasis on obsessionality in

comparison to compulsivity in OCI-R as compared to MOCI.

Another reason may be related to the differences between the

formats of two tests. The OCI-R is scored on a Lickert-scale

whereas the MOCI is scored with a true-false format.

Apart from the problem of item 16, neutralizing subscale it-

self is somewhat questionable in the original version of OCI-R.

The Cronbach’s alpha for this subscale was .34 (the lowest),

while the coefficients for the total scale and other subscales

were all high, ranging from .65 to .89 in Foa et al. study (2002).

Although in our study Cronbach's alpha for neutralizing was

good (r = .77), it was lowest as compared to other subscales.

We found the same trend in test-retest reliability (Table 4). The

correlation between this subscale with the total scale in our

study was .51, while the correlations for other subscales with

the total scale ranged from .63 to .76. As Abramowitz and

Deacon (2006) have indicated the findings suggest that the

neutralizing subscale is misnamed and possesses weaker con-

struct validity than other OCI-R subscales. It may measure

completely different construct than other items or the wording

(linguistic structure) of the item is complex creating some dif-

ficulties in comprehending this item, or there might be some

unique cultural aspect to this item that may not provide the

same meaning across different subgroups. Therefore, this item

can be considered as “attention” item that needs a careful re-

view and inspection.

We found that female students had somewhat higher OCI-R-

Persian total and subscales scores than males but this did not

reach statistical significance, except in the case of obsessing (t

= 2.27, df = 448, P < .05). No systematic evaluation of sex

differences were provided in the past OCI-R research (Fullana

et al., 2005). In our earlier studies with OCD patients in Iran,

we found significant differences between females and males (F

> M) in the total mean scores as well as in washing subscale of

MOCI. The same trend was found in CAC, but not in Y-BOCS

total or subscale scores (Ghassemzadeh et al., 2002, 2005b).

In conclusion, we found the OCI-R-Persian to be a brief and

time-efficient measure of obsessions and compulsions in the

general population in this setting. Participants had no difficulty

in understanding the questions. Thus, it is an ideal measure for

use for screening and epidemiological research in large general

population samples.

H. GHASSEMZADEH ET AL. 215

Future work needs to examine the psychometric properties of

OCI-R-Persian in clinical samples and its utility as a measure of

change of OCD symptomatology in clinical setting (c.f.

Abramowitz & Deacon, 2006). Future work also needs to as-

sess the potential utility of OCI-R in distinguishing OCD from

other types of anxiety disorders and depression in this setting.

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