One of the important and integral parts of teaching is evaluation (Rushforth, 2007). It comprises of many different forms of assessment. In the nursing curriculum, formal assessment includes the evaluation of clinical competence and that is fundamental in all health professional education (Walters and Adams 2002 and Mitchell, Henderson, Groves, Dalton and Nulty 2009).

To assess the clinical competence; Objective Structured Clinical Examination (OSCE) was introduced in the Medical education (Walters and Adams 2002, Ward, Barratt and Aston 2009, Bartlett, Simonite, Westcott and Taylor 2000). Since 10 years, there is an increase in interest in this form of assessment in health professionals including nursing (Walters and Adams 2002). In nursing education, assessments like OSCE has potential to test a wide range of knowledge and skills as compare to paper pencil tests which focus on a narrow range of the examinee's performance.

In nursing, OSCE is a structured assessment of specific, clearly defined clinical skills, in which students complete a sequence of practical examinations designed to assess separate components of a consultation requiring the use of advanced clinical practical skills, such as history taking and physical examination (Mitchell et. al 2009, Ward, Barratt, Aston 2009).

OSCE is the part of an effective assessment strategy of nursing competencies (Rushforth 2007, Walters and Adams 2002). It requires each student to demonstrate specific skills and behaviors in the simulated work environment with standardized policies and procedures (Mitchell, et. al 2009, Bartlett, et. al 2000). The short stations are assigned to nursing students to perform different ranges of tasks, which cover all the expected component of curriculum and provide a mixed assessment circuit which is assessed by different examiners using previously determined objective marking scheme (Walters and Adams 2002, Mitchell et. al 2009). This multi-station OSCE has been used for undergraduate nurse students to assess both advanced clinical practice skills and student's interpretation of findings (Mitchell, et. al 2009).

There are many advantages of utilizing OSCE as clinical skills assessment tool. It includes both summative and formative components of assessment which includes evaluation of performance and feedback; from which students can learn (Mitchell, et. al 2009, Bujack, McMillan, Jeanette and Mike 1991). It will also provide an opportunity to the learners to know about their strengths and short comings based on the feedback received. In addition to this they also become self-aware regarding their performance of the skills. Secondly, OCSE enables students to demonstrate required behavior in a simulated environment; by having strict control over the clinical context. (Mitchell, et. al 2009, Bujack, et. al 1991). It also reflects on the real life professional tasks. Thus, the standardized method of OCSE ensures objectivity and maximizes reliability in assessment with minimal harm to patients in real life situations (Mitchell, et. al 2009, Bujack, et. al 1991). Also, it is found that OSCE possess high face validity as both students' and examiners' can measure skills relevant to clinical practice (Mitchell, et. al 2009). Literature also supports OSCE as more reliable and valid than the other traditional forms of clinical assessment, such as long cases and viva voice examinations (Mitchell, et. al 2009). In an undergraduate nursing curriculum, OSCEs support safe practice of nursing students in terms of psychomotor skills performance, as well as declarative and schematic knowledge associated with their application. (Mitchell, et. al 2009, Bujack, et. al 1991).

The clinical component which is the ultimate goal to be tested through OSCE is divided into various components. Like, acquisition of clinical data in the form of history taking and physical examination, the interpretation of clinical data by problem identification and nursing diagnosis and the use of clinical data i.e. decision making through supportive, educative or therapeutic interventions (Walters and Adams 2002). The development and execution of OSCE provides a platform to the health care educators by facilitating joint ownership of the assessment process and reducing the theory practice gap (Walters and Adams 2002). The next part of this paper will discuss upon the utilization and challenges associated with OSCEs.

It is important to explore the use of OSCE within the nurse undergraduate curriculum to enhance the competency of skills used by nursing students'. In this article there are four major areas that describe best about the appropriate use and improvement in competency of OSCE.

While preparing for OSCE, it is important to consider the socio-cultural context of the simulated clients. It is proposed that combinations of knowledge, skills, attitudes and values can be brought together in context-specific situations (Walters and Adams 2002, Mitchell, et. al 2009). It is relevant to note that culturally simulated set up will allow examiner to check whether the performer is alert towards cultural sensitiveness and is able to deal with the client by demonstrating caring behavior.

Another important thing is to check the student readiness to perform skills as Gorman, Lazaro, Fairchild, and Kennedy (2010) said that it is important to look for safe clinical practice by students during the OSCE. The examples include the usage and handling of equipment, following recommended standards and maintaining aseptic techniques. As Creed (n.d.) said that sense of infection control is also necessary to assess during performance examination. It will enable the examiner to understand the attitude of student towards skill performance. This aspect of maintaining aseptic techniques is also highlighted by Creed (n.d.) who cited Nursing and Midwifery council (NMC) (2007).

OSCE will allow the examiner to assess competency of performed skills. It may include the order, organization, time management, dexterity, communication with the client and documentation. It is also found through research by Ogden, Green and Ker (2000) that if we include peers in the evaluation it will allow the student to feel more comfortable with their peer evaluations in terms of marks and feedbacks.

The comfort level will reduce anxiety and improve the organization in performing skills. Besides this, confidence level of the performer can be assessed while measuring the competency. Shawyer, S., Alison, C., Julie, D., Lois, G. (2007) cited Brown et. al (2003) that confidence is central to competency while assessing and performing clinical skills.

The examiner is also looking at over all professionalism like communication with the client or colleague, dress code, knowledge of the performed skill and able to handle unwanted moments. But before thinking about these aspects, it is important to have a checklist or mark sheet which will undertake all the hidden aspects of OSCE (Mitchell, et. al 2009). The thought to ponder here is that the creations of unwanted moments are either favorable or unfavorable for the students. It may distract the students resulting in low score or losing confidence level. However, it is important to assess students' for such hidden agendas so when they enter in real set up; they can deal with any emergency conditions.

OSCEs are performed in simulated environment and therefore it may give rise to few challenges for the examiners and learners. During OSCE examination, the environment offers the individual to behave in a socially desirable manner which may not truly reflect the way the individual would perform in a real world (Bujack, et. al 1991). Thus, one may query the OSCE's predictive validity for the psychosocial skills and such competencies (Mitchell, et. al 2009). Other major challenge which students might face during OSCE examination is that it prevents accommodating the countless culture, economic and socio-political context that exist within the larger clinical nursing context (Mitchell, et. al 2009). Hence, the level of competence in critical thinking assessed by OSCE is unlikely to fully reflect the students' ability to competently apply critical thinking in the real-life clinical setting. A part from this, the aspects that are assessable in an OSCE may be insufficient to confirm (or refute) the basic core component of nursing i.e. caring (Mitchell, et. al 2009). Thus, the assessment of complex and essentially subjective constructs, such as caring, empathy and other interpersonal skills are vulnerable to findings of low validity and poor inter-rater reliability within an OSCE (Mitchell, et. al 2009). Contextual information is needed again to judge the appropriateness of nurse's behavior; therefore, the extent to which psychosocial constructs, such as caring, are appropriate for evaluation using the OSCE approach is debatable (Mitchell, et.al 2009).

In order to conclude, one can say that OSCEs are helpful tool to assess nursing professionalism of the learners and it will allow the nursing educationist and administrative leaders to look for quality of care by improving safe care practices. During performing OSCE, if it is identified that there would be any harm to patient safety, then one can work on post skills counseling and prepare action plans to improve the nursing practice. Nursing students also feel comfortable and have sense of achievement regarding this type of performance based assessment (Walters and Adams 2002). They feel that this mode of assessment give them an opportunity to reflect on their nursing roles and functions and give them option to express their competence in clinical activities (Walters and Adams 2002); through integrating their theoretical knowledge (Walters and Adams 2002). It demonstrates their ability to apply principles, interpret data and respond to clinical situations (Walters and Adams 2002). It is also discussed that OSCE assesses efficiently the concrete, measurable aspects of clinical performance (Mitchell, et. al 2009, Bujack, et. al 1991). However, using OSCE mainly to assess technical skills and the underlying knowledge required for their safe and accurate application diminishes the impact of context specificity (Mitchell, et. al 2009, Bujack, et. al 1991). Thus, there is a need for variety of assessment methods to capture the diverse nature of nursing practice. It is only done by utilizing variety of appropriate assessment strategies, with a rigorous and valid assessment of individual's competency (Mitchell, et. al 2009). To sum up, OSCE will remain one of the best assessments to assess clinical competency in terms of performance.